I can field a few of these.
First, Mega-Att's. When you get the first dot of a Mega-Att you automatically gain one Enhancement at no additional cost. Any further increases to the Mega-Att do not add more Enhancement, they're purchased separately (I think for 5xp).
As for Hypermove, I couldn't say for certain if the hypermove as a level 3 power would allow for superfast swimming, I would assume it does. Even if it does not, this seems like a harmless enough perk to allow, particularly since you're taking both as level 3 powers.
Enhanced Movement would appear to modify that 500kph/dot amount by multiplying it by (M.Dex+1). The enhanacement does not explicitly modify flight, this would seem to me to be thematic. As a Mega-Dex enhancement, this Enhancement is presumably allowing you to move your limbs ultra-quickly to allow for faster movement. Flight is almost always accomplished via some other medium, or like Solitare, through no apparent medium at all (since she just sort of flies). The advantage of flight is, of course, in a combination of z-axis movement and being able to travel 'as the crow flies' by not being limited to roads/paths/etc.
Still, flying at 500kph
per dot in Hypermove (flight) makes you stupidly fast. The speed of sound (
http://en.wikipedia.org/wiki/Speed_of_sound) at sea level is about 1225 kph and is about 1062 kph at the cruising altitude of most jetliners. A mere two dot investiment has you right up on top of that and three dots makes you supersonic. For those more familiar with units we Americans use, each dot of hyperspeed is about 310mph outside of combat.
