So here you are questioning whether the days were mixed up by the changes made in the calendar over the years. What we know is that the changes in the calendar never affected the weekly cycle. Tuesday always followed Monday, etc, etc. What a change in the calendar affected was the date.
But remember who it was that created the Sabbath. God blessed the 7th day and hallowed it and set apart that day for rest and communion with him. The 4th commandment not only says to rest on the 7th day but says why as well. It says in verse 11 "For in six days the Lord made the heavens and the earth, the sea, and all that is in them, but he rested on the seventh day. Therefore the Lord blessed the Sabbath day and made it holy."
So God blessed the Sabbath and made it holy which means that you cannot pick which day you want for the Sabbath because it was given a special blessing and sanctified.
Now concerning Colossians 2:16. Verse 14 says, "Blotting out the handwriting of ordinances that was against us, which was contrary to us, and took it out of the way, nailing it to his cross;"
The reason for verse 16 is because the handwriting of ordinances was blotted out and nailed to the cross. The handwriting of ordinances was the law written by Moses, which was placed on the side of the Ark and contained rules concerning ceremonies, sacrifices, feasts and ordinances which were a shadow of the work that Jesus Christ would ultimately do. These things were a shadow.
Heb 10:1 For the law having a shadow of good things to come, and not the very image of the things, can never with those sacrifices which they offered year by year continually make the comers thereunto perfect.
Heb 10:2 For then would they not have ceased to be offered? because that the worshippers once purged should have had no more conscience of sins.
Heb 10:3 But in those sacrifices there is a remembrance again made of sins every year.
Heb 10:4 For it is not possible that the blood of bulls and of goats should take away sins.
Also look at:
Heb 9:8 The Holy Ghost this signifying, that the way into the holiest of all was not yet made manifest, while as the first tabernacle was yet standing:
Heb 9:9 Which was a figure for the time then present, in which were offered both gifts and sacrifices, that could not make him that did the service perfect, as pertaining to the conscience;
Heb 9:10 Which stood only in meats and drinks, and divers washings, and carnal ordinances, imposed on them until the time of reformation.
Heb 9:11 But Christ being come an high priest of good things to come, by a greater and more perfect tabernacle, not made with hands, that is to say, not of this building;
What was nailed to the cross was the sanctuary system and all the laws that came as a result of this imperfect system which was put in place temporarily as a shadow of the ministry of Christ. Where does the sabbath days in Cor 2:16 then come in? Every holy day in the sanctuary system was made a sabbath day in addition to the weekly sabbath day. But these Sabbath days were yearly which means it could fall on any day of the week. Whenever one of these ceremonial sabbaths fell on the Sabbath day it was considered a High Holy day. 1 Cor 2:16 is not referring to the weekly sabbath. It is referring to these additional sabbaths that were institutied as a part of the sanctuary system. Let me show you know that the Law that Moses wrote was separated from the 10 commandments.
Deu 31:24 And it came to pass, when Moses had made an end of writing the words of this law in a book, until they were finished,
Deu 31:25 That Moses commanded the Levites, which bare the ark of the covenant of the LORD, saying,
Deu 31:26 Take this book of the law, and put it in the side of the ark of the covenant of the LORD your God, that it may be there for a witness against thee.
Moses Law was placed on the side of the ark
Deu 10:5 And I turned myself and came down from the mount, and put the tables in the ark which I had made; and there they be, as the LORD commanded me.
The 10 commandments were placed in the ark
Moses Law contained rules concerning the monthly and weekly sabbaths, and special holy days such as a the day of atonement. God's 10 commandments commands the observance of the 7th day Sabbath which was instituted as created, long before the Sanctuary system was put in place.
Deuteronomy: 5. 12. Keep the sabbath day to sanctify it, as the LORD thy God hath commanded thee. 13. Six days thou shalt labour, and do all thy work: 14. But the seventh day is the sabbath of the LORD thy God: in it thou shalt not do any work, thou, nor thy son, nor thy daughter, nor thy manservant, nor thy maidservant, nor thine ox, nor thine ass, nor any of thy cattle, nor thy stranger that is within thy gates; that thy manservant and thy maidservant may rest as well as thou.
By what means do you know the first or the last day?
Six days thou shalt labor,and do all thy work.
But the seventh day is the Sabbath.
God does not mention a certain day,He commands a rest on the 7th day from your work.
Have you considered the Wisdom of God in knowing one day there would be millions of working Christians ?
Not all work Sunday through Saturday.
Not to mention world time difference.
No you cannot change the Bible to fit a doctrine:
Colossians: 2. 16. Let no man therefore judge you in meat, or in drink, or in respect of an holyday, or of the new moon, or of the sabbath days: 17. Which are a shadow of things to come; but the body is of Christ. 18. Let no man beguile you of your reward in a voluntary humility and worshipping of angels, intruding into those things which he hath not seen, vainly puffed up by his fleshly mind, 19. And not holding the Head, from which all the body by joints and bands having nourishment ministered, and knit together, increaseth with the increase of God. 20. Wherefore if ye be dead with Christ from the rudiments of the world, why, as though living in the world, are ye subject to ordinances, 21. (Touch not; taste not; handle not; 22. Which all are to perish with the using

after the commandments and doctrines of men? 23. Which things have indeed a shew of wisdom in will worship, and humility, and neglecting of the body; not in any honour to the satisfying of the flesh.
Here is the rest of the passage,notice the touch not taste not handle not,they are doctrines of men not God.
Paul was rebuking knostisism in the Hebrew people who tried to subvert His teaching of the Gospel of Christ.
Trying to abide in a doctrine given by a prophet of another Gospel ,that contends on many points with the plain truth of God's Word is false doctrine.
The Old Testament is truth and God's word,God has not Changed,Christ has fulfilled the law.
Galatians: 3. 9. So then they which be of faith are blessed with faithful Abraham. 10. For as many as are of the works of the law are under the curse: for it is written, Cursed is every one that continueth not in all things which are written in the book of the law to do them. 11. But that no man is justified by the law in the sight of God, it is evident: for, The just shall live by faith. 12. And the law is not of faith: but, The man that doeth them shall live in them. 13. Christ hath redeemed us from the curse of the law, being made a curse for us: for it is written, Cursed is every one that hangeth on a tree: 14. That the blessing of Abraham might come on the Gentiles through Jesus Christ; that we might receive the promise of the Spirit through faith.
If you want to vow a covenant before God,I do not condemn you for this.
Romans: 14. 1. Him that is weak in the faith receive ye, but not to doubtful disputations. 2. For one believeth that he may eat all things: another, who is weak, eateth herbs. 3. Let not him that eateth despise him that eateth not; and let not him which eateth not judge him that eateth: for God hath received him. 4. Who art thou that judgest another man's servant? to his own master he standeth or falleth. Yea, he shall be holden up: for God is able to make him stand. 5. One man esteemeth one day above another: another esteemeth every day alike. Let every man be fully persuaded in his own mind. 6. He that regardeth the day, regardeth it unto the Lord; and he that regardeth not the day, to the Lord he doth not regard it. He that eateth, eateth to the Lord, for he giveth God thanks; and he that eateth not, to the Lord he eateth not, and giveth God thanks. 7. For none of us liveth to himself, and no man dieth to himself. 8. For whether we live, we live unto the Lord; and whether we die, we die unto the Lord: whether we live therefore, or die, we are the Lord's.
Simply do not condemn others who do not keep Mrs Whites vision of rules to live by.