Does about 100 000 sound reasonable through more active immigration from France and other European ares
I'll have to look into it, but that still sounds reasonable. Remember they all have to be A) Catholic, B) settlers wished to try their luck in the balmy sugar islands, and C) the
reputation of New France (especially Canada, Acadia was known to be relatively prosperous...but the peninsular part was now Nova Scotia by your POD and the New Brunswick area was a disputed no man's-land) was daunting as a cold, whore-infested place (yes). So you have to change that or force more settlers to go in anyways.
Basically have Louis XV force more direct subjects go to New France, maybe recruit some down-on-their-luck peasants from neighboring areas who will already be/become Catholic and swear fealty, and it's plausible as long as you do it over a long enough period of time.