Guppies are great community fish and can live quite happily with most Tetras, Rasboras, Barbs, Anabantids, Dwarf Cichlids, Danios, Corydoras and many other species provided they don't get too big and eat the guppies.
yes
No Guppies are not moss eaters.
No
You should wait until the baby guppies seem to be big enough.
You could add a shoal of guppies and simply allow them to breed which would certainly stock your tank well
put the guppy fry in a different tank because the adult guppies will eat them
What are guppies
Guppies are community fish that should never be kept alone or in bowls they require large tank, at least 10 gallons.
I had a problem like this, a couple of fish pregnant at the same time. I would either keep them all the female guppies in the birthing tank or keep them in the community tank and when one of the female guppies give birth put the baby in the birthing tank. I did the second option and it was quite good, just don't overcrowd the birthing tank. :)
Bristlenose catfish
no
About 5 or 6 guppies.