"had" or "has"? Huge difference! I will assume "has".

Edit: oops, yeah, "have", not "has". My bad. :P

Arguably Melissa had four and thus they have four, eh?

“Have” is the word you are looking for, “has” isn’t grammatically correct. However, “had” in past tense is also correct, as it refers to the fact that they were born in the past, it does not imply (as you seem to be saying) that the children aren’t alive anymore.

sorry I changed to “have”.