What goes in determines what comes out. There's no real set bioload for a particular fish. Granted some fish like plecos seem to poop a whole lot more than others. If a pleco is a 10 for being the poop master, then an angel would be somewhere around a 4 I think.
Dude, it's a 125! A few angels would not overstock it, you probably wouldn't even see any spikes if you added 3 full grown adult angels with that amount of water.
Are your glowlight tetras actually Glofish (GM danios), or are they the naturally-occurring glowlight tetras? If they are the tetras, you probably don't need to move them. They are not nippy, so they pose no threat to the angels, but they grow larger than neons, so it's doubtful IMO that they will be eaten. I kept glowlights with an adult angel for a long time, no issues whatsoever. You'll need to find out what species your other tetras are, just to make sure they are not nippers. My other major concern here is the gouramis... some people get it to work, others have huge problems mixing angels and gouramis. I've never done it so I can't really wager a guess, but I suppose it's best to have a back up plan in case it doesn't work out, even if that means a Rubbermaid bin with a cheap heater and filter. You know if things go haywire it will happen like 10 minutes after the LFS closes when you can't return the fish! I'm not sure if the geophagus will be a problem for angels, but I doubt it if he's not a problem for the gouramis.
Oh wait I just saw that it was a 125. Then definitely! I agree with severum on the angels and gouramis. I believe that geophagus is pretty peaceful, but I guess it might depend on which species you have.