The Late Period of Ancient Egypt

I've recently been reading up on Ancient Egypt, and then specifically its religion and the zenith of its power, prosperity and influence under the Eighteenth Dynasty during the New Kingdom. You know, the standard fare when it comes to Ancient Egypt.

However, Egypt's history didn't stop at the New Kingdom, so I've also been reading up on the Late Period, when Egypt was reunited under first the Twenty-Sixth Dynasty, which vied for influence and power with Babylon in the Near East, and then (after Persian conquest) the Twenty-Eigth, Twenty-Ninth and Thirtieth Dynasties, lasting from 404 to 343 BC, the last indigenous dynasties ruling Ancient Egypt.

But since there's so little information about these later dynasties on the Internet (the same probably goes for mainstream literature, too), I'm left wondering: how did these final indigenous dynasties look? How, and with what, did they project their power? What was the status of Egyptian culture in its last period of self-rule?

Particularly, how did the Egyptian army look during the Late Period, and then specifically under the Twenty-Sixth Dynasties, and then the Twenty-Eighth through to the Thirtieth Dynasties? Was it anything like the military of the New Kingdom? Or was it more a carbon copy of the Assyrian (and later Persian) forces that had carried so much before them? I know several Greek powers involved themselves in Egyptian affairs during the last dynasties which had rebelled against the Persians (particularly Sparta) and I've read of the Spartans hiring themselves out as mercenaries to the Egyptians, but how widespread was this?

Does anybody around here know?