Some anonymous person did a study on the 12 and may be somewhat of an enlightenment for you.
The Twelve Tribes
I will post the relevant part here but feel free to check out the rest:
The Twelves Tribes in Revelation 7
Twelve tribes are listed, but the list in unorthodox
it doesn't follow "standard" orders
it lists Levi and doesn't list Dan
it lists Joseph and Manasseh, but leaves Ephraim out
What possible reason could there be for this list?
the out-of-order reasoning
it has been noted that if verses 5c, 6 (Gad to Manasseh)
were moved after verse 8
then the rational (mother) order is almost restored
this requires us to believe that a transcription error was made
that some scribe got the order wrong while copying
this still does not explain why Manasseh replaces Dan
the antichrist reasoning
Hebrew tradition suggests a reason for omitting Dan
the antichrist is supposed to be of the line of Dan
so leaving him out of this list makes "sense"
the idolatry reasoning
Dan was early connected with idolatry
Judges 18
some people think that this could explain their loss
as a tribe they aren't (weren't) worry of this list
neither of these last two explain Joseph, Ephraim, and Manasseh
why is Joseph back?
why is Manasseh here but Ephraim not?
Let us look at this somewhat differently for there is a fact of Hebrew custom that we are ignoring and which we usually ignore when interpreting the bible unless we are hit over the head with it
Genesis 29:31 - 30:24, 35:16-18
the sons are named by their mothers (and father in one case)
for particular reasons the names mean something
Let us examine the list in Revelation along with the meanings
Who's listed?
Judah praise or Praise the Lord
Reuben see, a son
Gad good fortune
Asher happy
Naphtali my struggle or obtained by wrestling
Manasseh causing forgetfulness
Simeon one who hears or hears and obeys
Levi attached or joined
Issachar reward
Zebulun honour or looking for a home
Joseph may God add
Benjamin son of the right hand
Who's not listed?
Dan he has vindicates or he that judges
Ephraim doubly fruitful
What's it mean?
who does this list describe
the 144,000 servants sealed by God
what purpose does enumerating them serve?
couldn't one have just said
12,000 from each of the tribes of Israel?
How about taking the meaning of the names into consideration
Those who praise the Lord Judah
seeing the Son Reuben
in good fortune Gad
and happiness Asher
but wrestling Naphtali
with forgetfulness. Manasseh
Hearing and obeying Simeon
and joined, Levi
as a reward Issachar
looking for a home, Zebulun
added as the Joseph
son of the right hand. Benjamin
we've lost an interpretive tool over the past centuries
we have forgotten what the names meant
since our names rarely "mean" anything.
except to expectant parents