Potential fish breeder?
If I were attempting to become a fish breeder, I would not try in a community tank.
I would start with single species tanks with live bearers like guppies, platys or swordfish. Once I had basic genetics down and could breed for about any improvement I desire, I would then switch to easy egglayers such as convict cichlids or zebra fish.
Then I would try an air breather like gouramis or bettas. It is hard to get them past the 2nd week after hatching.
Some tetras and some barbs are easy to breed.
Now as to your loach. Don't use those species you mentioned. You won't see most of them in the community tank, they (except for the Clown) will hide all day and only come out at night and larger angels might think that you have given them a nice dinner of worms.
Look at the Reticulated Hillstream Loach. Not as shy as many of the loaches, and quite a looker. It does like heavy water flow just like the other loaches, but you can often find the stream like flow that is still comfortable for other tank mates.
Clowns will hide some, but not like the other loaches you mentioned. Clown loaches will pull on threadfins like on the angels. Clowns grow quiet long and are heavy bodied. You'll need extra space in your upgraded aquarium. (Note, I personally know of exceptions to the threadfin pulling behavior, I am speaking of the majority of clown loaches. Individuals may vary in behavior)
Now, that I stated that, remember that if you do go with a thin body loach such as the kuhlie loach or dojo, it does not have quite the bioload of a heavy body fish. I would estimate 4 per 2.5 gallons in comparison to a single 2.5 inch heavy body fish for the same 2.5 gallons.
A low light level plant? How about a plastic one? No? Okay, for angel fish I would use something where the leaves are just big enough for them to lay eggs on, such as Anubias barteri v. Nana.
Oh, dojo and kuhlie loaches are highly social. I would not go with less than 6..
im upgrading in about 6 months to a year to 50= gallons so pleco will be alright
