help me find my 2nd fish species

[elmer]

Well I've had my 3 baby keyholes for 5 days, so time to think about the remaining fish I want to put in the tank, lol. Actually I love these little guys - they are so active and curious.

But I love the choosing as much as the getting - I obsessed for a month about what car to buy when my old one went kaput for example.

I have a AquaClear 50 on this 20G tank. There are some plants which I hope will keep growing: moneywort, java fern on driftwood, american val. I might add a carpet plant or a small crypt sword in front.

As I mentioned in another thread, I have pH 8.1. Same pH as my tap water, and it's been stable like that in the tank for a month.

I do 25% water change weekly.

I have crushed coral with a bit of regular gravel. Now looking at the coral a bit closer I realize it's tumbled and not really sharp.

I'm thinking one of the following:
a) 3 or 4 platys
b) 3 or 4 swordtails
c) 1 angel
d) 1 male Betta splendens
e) 2 or 3 female Betta splendens
f) 2 rainbowfish of some kind

I'm not looking for a bottom swimmer, as these keyholes like middle-bottom mostly.

My concern about the Betta is apparently they don't like a current. There's a pretty strong current at the outlet of the power filter.

My concern about the angel is it may not like the high pH. However, my guess is the local fish stores have ones that are acclimatized to this.

And then the rainbowfish are generally schoolers, so 2 is not enough.

And then I think platys or swordtails might be boring. Waiting to be convinced otherwise though.

Honestly I'm leaning towards a male betta plus an angel.

So, what do you think? Any other ideas? Any thoughts on the above?