Seven years is a mighty long time to be deprived of Tactics.

You first meet Aeris in Zarghidas Trade City where she offers to sell you a flower for 1 Gil. You should accept!

To get Cloud you have to go through the rigamarole of getting Berowulf, Reis, and Worker 8 first.

Once you defeat Worker 7 New, you should go back to Goug Machine City, where Cloud should then appear. Follow him to Zarghidas, where he saves Aeris from thugs, but then needs saving by you.

By this point you will have recruited every non-generic character except for Byblos.