Rummynose tetras have a similar shape to neon tetras and would also get eaten quite readily. Any small neon-like tetra (including young cardinals or rummies/fireheads) will get eaten by adult angels. Tetras like black phantoms don't get eaten because of their shape. Bloodfins wouldn't get eaten because of their size (though, like the rummies, young ones would). I'm not the biggest bloodfin fan but they are a decent fish and I think that if you like them you wouldn't get bored of them. However, I'd suggest a big school if you want them to have some impact on the set-up. I'd say to get at least 8 (I assume they are the silver dollars' replacement?).
You mentioned adding 2 extra gouramies. Probably not a good idea. Stick to the ones you have planned as gouramies and angels occupy the same areas in the tank and you realy don't want to over-crowd these sorts of fish. Also, I urge you to make sure the gold and opaline gouramies you want are both female, added at the same time but after the pearls and are of the same size. They are both the same species (trichogaster trichopterus) and can get rather aggressive with each other and other gouramies though it's the males that cause most trouble.
As for livebearers that would work... Guppies are risky. As is anything smaller such as mosquito fish or enlder's. Stick to platies and swordtails. Still, juveniles under 1" are at risk from adult angels. I expect you won't have adults though anyway when you first add the livebearers so this won't be an issue unless you want fry (which will get eaten). Mollies would also work, in theory, but I don't like mixing them with gouramies.
I don't recall whether or not you were going to have any bottom-dwelling fish in this tank. Maybe consider something like that as an addition to balance out the middle and, particularly, the heavily-stocked top. You'll probably want, BTW, to have plenty of floating plants or tall rooted plants in this tank to provide enough territories to keep aggression down between the gouramies, offer hiding places and also make the angels feel comfortable enough and keep aggression down if they turn out to be a pair and breed.