Pre Purchase Questions Please?

[JewelSki]

Hello,
Im just deciding which theme I am going to purchase along with the Genisis Framework and have a few questions first

1, Say I really like a theme but in the theme description it says nothing about custom backgrounds/header and it says choose from 3 colour schemes,,,, but I dont want any of those colours and I do want to add my own background + header and my own colour scheme,,, can it still be done or do I need to choose a theme that states custom backgrounds etc?

2, I have tried to go into the individual theme support sections to read more about the ones im deciding against but I dont have permission, so when I do make a purchase, how do I get permission to go into that section of the support section?

3, Since I will be adding a small shop, does anyone know if these themes work with the wp ecommerce plugin? Its just because I already have that and I paid for the upgrade to the gold cart so I could have multiple images and it also connects with Australia post automaticlly,,,, I cant find any info for Woocommerce if it has the ability to add multiple images and I would need to pay for the Australia post add on,,, I dont really mind if I go the Woocommerce way at all as long as its a lot better that wp ecommerce, seems silly though if its not as good and I need to pay more for things I already have.

Sorry for a long post but would greatly appreciate any advise before I make the decision :)