Philoctetes

Well, then they can be, say, just Sarissophoroi (basic unit) and Chalcaspides (champions/guards/etc,).

Yes, sounds quite correct. Sarissa-bearing Agema remained in the Ptolemaic army definitely at least till 103 BC (so-called "The War of Sceptres" and the battle of Asophon where Alexander Jannaeus' Jewish army was soundly defeated by Ptolemy IX - then in exile; see Jos. Ant. Iud. XIII. 12ff), and maybe ever later. Can be simply "Chalcaspides"; Josephus specifically mentions the brazen shields (προμαχοῦσιν ἐπίχαλκοι αἱ ἀσπίδες – Ant. Iud. XIII. 12. 5).