@Randy Dandy,
Hmm.
I just noticed you posted 2 values for square feet per acre in the OP.
Correct is 43,560. Dividing by 16 gives 2722.5 trees.
From a practical value, if I were the landscaper, I would agree with my supplier for 2700+/- trees. (They probably would estimate) After planting has progressed, I would arrange to fill in with those needed, or return excess.
You need to proof read your posts.