Some thoughts and my 2cents:
No liveaboard neither from Aqaba nor from Eilat.
Aqua sport in Taba have a boat for dailies to nearby sites and they have one capable for libraboard to Dahab and back, but not sure how frequent they operate, and probably only if there is demand, as this is not the mainstream of Sinai dive scene. But even daily boat is actually cool and nice. Pharaoh island in my opinion is the least interesting site. Taba itself has about two dive sites, which are nice and healthy. With good air consumption one can do both in the same dive.
Aqaba: the only dive site that really necessitates a boat is the power station. All others are really easy to access from shore and it actually takes more time to reach by boat. Your preference.
There are about a dozen popular sites, some are big enough to be splitted into subsites. Ask of them are nice in my opinion, although as already stated, they are no match for Dahab, Sharm Ras Mohammed etc.
But Aqaba is relaxes, and can be combined with Petra and other attractions.
If you haven't dived red sea, it can be nice vacation. Don't expect big animal encounters. Biggest you're likely to see is an occasional Napoleon Humphead Wrasse, with some luck a turtle. Oh, there have been some rare spottings of Manta Rays, but really don't count on it and don't hold your breath while looking for one.
