To what you are saying about "yom", I have a different understanding. This is a quote from Ken Ham's book "The New Answers Book".
"Yom is defined the first time it is used in the Bible (Genesis 1:4-5_ in its two literal senses: the light portion of the light/dark cycle and the whole light/dark cycle. Second, yom is used with "evening" and "morning". Everywhere these two words are used in the old testament, either together or seperately and with or without yom in the context, they always mean a literal evening or morning of a literal day. Third, yom is modified with a number: one day, second day, third day, etc. which everywhere else in the Old Testament indicates literal days. Fourth, yom is deined literally in Genesis 1:14 in relation to the heavenly bodies."