Wifi connection shouldn't be a problem. Regarding the updating: let's just say I'm happy I did that the evening before I showed the Wii U to my kids
Grabbed a copy of Nintendo Land for Ł15 from CEX - so looks like I'm all set this evening as the Wii U has arrived and the wife is standing guard over it cos looking after 3 kids doesn't keep her anywhere near busy enough.
So a bit of multiplayer Mario Chase and New Super Mario Bros U is on the cards. Assuming I can get it connected to my wi-fi and updated. Yeah, I've been reading about that, sounds fun.