Epilektoi Hoplitai were a group of very good hoplites, while the Hypaspistai are the Hellenistic Royal Guard, an elite unit. Hypaspistai are meant to be strong, and in close combat very hard to defeat.

The hypaspistai can either use spear or sword. They charge with spears and usually fight with swords, if you command them to fight with spears (good vs cavalry), they will do so, but change back to swords after some time.

If you had given the hoplitai secondary swords, the AI would use the swords the most. This would be ahistorical. Just take a look at the Iphokratous (spelling?) hoplitai, in hands of the AI, they usually grab their short swords, even in situations where they really shouldn't.

Your STARTING family members with the Spartiatai ethnicity will have Spartiates Hoplitai as Bodyguard, while all others have Somatophylakes Strategou, any Spartiatai family members who come of age will get the regular bodyguards too. Enjoy them while you can!

Hope that helps!

~Fluvius