OK, I'll try to answer your original question.
Without having checked each sensor you posted, I will just assume that they are all analog.
The Uno has 6 analogue inputs, so that wont work (except if you multiplex them, but lets not go there.)
The Mega has 16 inputs, so that should work for you.
I would chose XBee over wifi. You can use XBee to connect your project to a computer, and then use the computers wifi. Is probably simpler.
Just wondering what type of project uses all those sensors and is portable... 
If you use XBee I would look into the Fio. It can be programmed over XBee and it has 8 analog inputs.
Anyway
My 2c.
cheers
p.