I agree with most of what is posted above. I also responded in this thread:
I would like to see you update your "my info." with more details. In addition to having a huge bio load for a new tank I question if you have adequate filtration with only 40lbs of LR
and..."Canister filter and power filter" without knowing what kind of filters. Are you running a protien shimmer? The type of fish you have can be messy and I would recommend it down the road.
As for returning fish I agree that the agressive fish can go and possibly all if you truly have ich. My question is what LFS
is going to take back fish that may or may not have ich? Do you have a QT tank? A QT tank may be the better route long term. You can proberly QT your current fish you plan to keep and then QT furutre purchases and not run the risk of reintroducing disease. For the cost of a bare bottom 20g and extra HOB
with sponge it is worth the investement vs. the hassle of treating the main once it is infected.
Suggest you do some more research on the fish you want and develop a wish list. Fish should be added in a certain order from least aggressive (not necessarily the smallest) to most aggressive.
Don't give up, just slow down. Even with a 80 gallon tank you are limited on the amount of fish and if the filtration is less than adequate you may be even more limited.
Keep us posted on what you decide.