I'd skip the wheel upgrade... and by that I mean "upgrade".
As for the 105 upgrade,
AFAIK 8, 9 and 10 speed Shimano drive trains all use the same width hub and are all completely interchangeable (with the notable exception of the first Dura Ace 10 speed group, they had different hub splining. I skipped 8 speed though, so I could be off. 7spd had 126mm hubs and 8, 9 10 all use 130mm, and just used a narrower chain each time. 11 speed also uses a 130mm hub but the actual cassette body is wider to fit in all those cogs, so the overall hub width is the same but the amount of hub available for cassette is wider. You can use 8, 9 or 10 speed cassettes on an 11 speed hub with a spacer (Campy is different of course)