- after a female cat give birth, when can she be neuter? have to wait how long?

2 months(done to my cats)

- what is the best age for kitten to be spay/neuter?

with experience vets can be done at 2 months- if not so experience vets they will want to do it at 4-6months (better bf the 6th month)

- can i spay/neuter cat after vaccine?
can


- i heard they said, spay/neuter your cat when he/she is 100% healthy... what kind of healthy, is it like sick, or other desease like FIP/FIV/leukimia?

This once again depends on the vet- my vet will say is ok as long the cat is eating right/ poo and urine shows no signs of illness....is just like us human is better to make sure we are fit to an op.
Is better to make sure the cat is in a condition (fit) to go thru' an op.