FUSD71,
I'd like to suggest we slow down......maybe even back up a little bit.
If I'm following this discussion, right now your plan is to put 4 assorted damsels, a cardinal and possibly another fish into a 20 gallon tank......with cycled water......until your 90 gallon has cycled. At the same time you'll be leaving a yellow tang, hippo tang and flame angel with your lfs until the 90 cycles. At the end of the 90 cycle you plan on putting all these fish into it.
A couple concerns about this plan:
---There's a "rule of thumb" about how many/how much fish should/could be kept in a sw tank......one inch of fish for every 5 gallons . Without your unnamed fish, you're probably at or slightly over that limit.
---Probably not a good idea to keep two tangs in a 90 gallon tank. The tank is too small to provide adequate swimming room for two adult tangs.
---Not a good idea to put tangs or a flame angel in a newly cycled tank. These species require a more mature environment. The dwarf angel is a grazer and needs/likes lots of algea to nibble on......which it won't find in a newly cycled tank.
Okay, and if that's not bad enough:
---You don't mention what you're using as filtration for the 20 temporary housing tank. Is it a filter that has been in use on that tank, as sw, for some time? Has that tank had sw fish in it recently? If no to either or both of those, it's very likely the 20 will cycle shortly after you put the 4 or 5 fish into it. A tank is "cycled" when the bacteria in the biological filtration system (filter, live rock, live sand) can keep up with the bio-load ( waste products and decaying, uneaten food). Even though the water you're putting in the 20 is cycled, the bioload will become unbalanced when you put 5 fish in a small tank with (I'm guessing) inadequate filtration....and you'll begin a cycle.
Maybe I have guessed wrong and am reading too much into what you've not said. I hope so. If I'm right, though, I think you should set-up the 90, return all those fish to the lfs and try to get some store credit for future purchases. Then, when the 90 is ready, begin to add fish.....slowly.......
(Set up the 20, too. You can use it as a quarantine tank when you begin to stock your 90.)
Jim