Don't train any learning skills to Lv5 nigra. ._.
Edit: Now that I've read the entire post, lawl. I dunno if its 8 or 12, but I know that Carrier ships can carry more than 5. Haven't done any research on them though since I'm not too interested in getting a ship I'll never get to leave.
Drone velocity, I dunno. He was probably talking about the MWD speed they have when they approach a target, and not orbiting speed, which is probably what you were looking at.
To make your Cruiser go faster, pop on an Afterburner. Make sure you have the skills in Navigation trained up to use them though. For missions you can only use Afterburners. In open space for PvP and whatever, you can use Microwarpdrives, which make you go waaaaaaaaaaay faster than Afterburners.
About sentry drones, no clue honestly. I'm new to Gallente myself, but I know they have a max range of 80km-100km or something like that, when you have the proper skills and drone upgrades equipped on your ship. I'd go for T2 drones before you go for Sentries. Scout Drone Operation V and Drones V is all you need I think. You might need the "Gallente drone specialization" skill up to a certain amount too, not sure honestly.
But.. yeah, I'm going for T2 drones before I go for the Sentry/EWAR drones myself. D: