How many endlers could i comfortably fit in a 5.5 gallon?

It is planted and they would be with 5 red cherry shrimp and an oto.

I find that it is not a question with endlers. If you put a pair into that tank they will expand their numbers to some level that is intolerable and then you will never see a population growth again. You will always have fry in the tank mixed with the adults and probably stabilize the popualtion at around 40 fish. If you then remove the adults, the population will expand for a few months but eventually stabilize at the same level as the time before.
My 45 gallon usually has about 30 or 40 adults and an uncountable number of fry in it. When I sell off most of the adults at a club auction, the number of adults spikes to about 50 adults before settling back to the 30 to 40 range.

Hmmmm thats alot of fish, but i say i get only males how many in that saze tank?

If you buy a high quality filter and use plants that absorb ammonia you could fit about 10 in there.

But they wont be alone? They will be with shrimp and an oto.

I find that ELB are best kept based on theirn own heritage. I keep type N naturals as mty prinmary groupiong. Since many possibler grouopings are possible, you msu dedcde which of the various pssible