If and when Mr. Colling takes over Longbourn, I assume he would give up/lose his living. Would he then take over the exact earnings of Mr. Bennet and live in the similar condition of having little money on which to live?
Also, say he does take over Longbourn, if he and Charlotte fail to have a son and he passes, will Charlotte and any daughters they have had be in the same position as the Bennet ladies? What would happen to Longbourn then?