Well, for the beginning Pantodapoi Phalangitai are good and (rather) cheap line holders, plus they got AP axes. Them, doubled with Machimoi and Thoureophoroi/Ioudaioi Taxeis/Peltastai can give you a solid army. That's not counting missile troops, of course, which you surely will have no trouble recruiting in the East.

So basically there are quite a few units that are good playing as the Ptolemaioi, you just need to find out the best way to combine them.

Maion