First off on the angel- how tall is the tank. Minimum height for these guys is 20 inches (50 cm)
Guppies will be fine
Danios- very social and fast swimmers. Need groups of 6+ and tanks that have a minimum length of 4 feet.
Upside downs- all I know is they need minimum group of six (I think!) and they may? Grow to 6 inches???
Upside Down cats should be kept in groups of 6, I think your tank has the space, but I may be wrong. They only get about 4 inches long as opposed to the suggested 6, though that's still pretty large to fit in a school in a 2 foot long tank. I'd suggest getting a school of cory catfish instead, much more active and full of personality, my upside downs used to just hide all the time. They can also be a tad aggressive, in a sense, I used to see them chasing my other fish around sometimes at night, though I couldn't tell if it was hostile or not, really. Julii cories are amongst my favorite cory cats in trade. You can also try some small loach species like khuli loaches or yoyo loaches, rather than the upside down catfish or cories.
There are plenty of danios out there, though I'm assuming you mean zebra danios. Despite their small size, these fish are extremely active. Although they would do better in the assumed 4 foot space, due to their cheap price and how easy they are to find in aquarium trade, a 3 footer imo is adequate, and a 2 footer is tolerable, though not desirable. I'd suggest rummy nose tetras or harlequin rasboras instead. Either one you could easily get away with 8-12
If you get a single, regular, non veil tail angelfish, it should be fine in the space you provide.
Guppies are kinda tacky if you ask me. But you could get like 5 of them or so if you really want to. But imo, if you have a bunch of fish like the angels and catfish and naturally colored schooling fish, a bunch of pastel neon colored guppies would stick out like a sore thumb. I'd scrap them completely, but at the same time, I'm not a huge fan of livebearers. They've just been over bred in trade so much they've turned into plastic cookie cutter fish in my eyes .