I think so.
I am assuming you mean are guppies a good food for Oscars. Yes they are provided the guppies are free from disease.
No, guppies are fish.
The tiger fish would eat the guppies.
Guppies are a type of fish. There are no types of guppies.
Almost any community fish will do fine with guppies. Bettas are not a good idea with guppies because they will fight each other.
Guppies will survive with a school of clown loaches (Botia macracantha) for a while. Eventually they will be eaten.
Fish that have long, wavy fins should not be put with guppies, because guppies will nibble their long fins. Also, many bigger fish will eat guppies. Keep a separate tank with guppies and a few "cleaner" fish, which do not harm guppies.
Only guppies breed with guppies naturally.
Guppies are omnivores and do OK on normal Tropical fish flakes.
Guppies are freshwater fish: Sea horses are saltwater fish
Guppies natural enemies are bigger fish. When guppies are eggs diffrent fish and sea creature will eat them.
No Clown fish are good with guppies although it is possible to keep clown loaches (Botia macrocantha) and Guppies together for a while. Don't forget though that Botias are shoaling fish so they should be kept in groups. They also grow to around 14inches long so need a large tank.