What changes the finch canary dove questions answer
Plan for at least a compatible pair unless an avian professional gives a specific reason otherwise.
Same species is simpler
Mixing finch species can create bullying, breeding problems, diet mismatch, and stress.
Space matters
A pair still needs a wide flight cage, multiple perches, feeding stations, and room to avoid each other.
Sex matters
Male-female pairs can breed; same-sex groups can still fight. Learn the species before choosing birds.
Best default
Choose compatible finch company and enough space before buying birds.