It is difficult to recommend species without knowing the source water parameters, but while waiting for those there are a couple issues already mentioned and others not that I might be able to help with.
You asked about adding shoaling fish (danios here) together or separately...always add the entire group of a shoaling species if you can. They will always settle in faster with less stress, so less risk of ich appearing. Species that may have a pecking order or develop an hierarchy within the group will have fewer issues; adding more later with such species sometimes ends in dead new fish.
I certainly agree that the Rainbow Shark should be left out. Individuals vary in temperament, and while generally somewhat better than the closely-related Red Tail Shark, it is still a risk with any other substrate fish, and sometimes upper fish too.
The pleco must have real wood to graze; wood is needed to digest to prevent intestinal problems.
Giant Danio, Devario aequipinnatus, is a shoaling fish that must be kept in a group due to its high level of interaction; 8 is considered the minimum number. Their activeness makes them unsuited to any slow or sedate fish [like angelfish and rams], and they are best with medium/larger danio, peaceful barbs, and loaches. Several sources mention their boisterous aggressiveness including fin nipping, and this will more likely be curtailed and confined to "play" if a group of 8 or more are kept in a 4+ foot tank with suitable tankmates. These fish are jumpers, so a tight cover is a must. If the 60g tank is not 4-feet in length, I would select a different fish than the giant danio.
Bolivian Ram...this species is best as a lone specimen, or as a bonded pair. There is not space in a 60g for more than one male. By bonded pair is meant that the fish have selected each other (male/female) and bonded. This is more likely to succeed, though nothing is guaranteed. I can explain how to find a bonded pair if asked.
Angelfish is a shoaling species and best in a small group (five minimum) but there is not space here for that, so a lone specimen would be best even though I do not like to suggest keeping any fish contrary to its expectations. [In case you are wondering, a lone Bolivian Ram is fine as observations in the habitat suggest they live in isolation except when spawning.] The angelfish might be OK with the Bolivians, or might not, impossible to say as fish temperaments may vary. It will however be a major factor in finding tankmates, which will have to be fairly quiet fish--opposite of the danios. Rasbora are usually OK from this aspect, but not the dwarf species that will easily get eaten. And some of the disk-shaped tetras that are not active, like the Rosy Tetra, Red Phantom Tetra, etc. Any possible fin nippers have to be left out, species like the Red Minor or Serpae Tetra, Black Widow/Skirt Tetra, etc, as these will harass angelfish to death.