Try the html or flash website templates at Host Gator. I use them and they are excellent. There are a number of categories where you could go and select the pet category.

For #1 A website builder or web hosting site with web building tools all aim at helping you get your website up as easily as possible. It is more like a Wizard that helps you design your website.

For #2 If you would like to tinker more with your website you could use web design software like front page or dream weaver or Kompozer. I actually use Kompozer. It is really simple and free to use. Use any of these and edit your preferred template that you have downloaded and upload using an ftp program which you can locate if you google "free ftp program".

For #3 you can get an ecommerce site with shared hosting. So I would advise that you start with shared hosting and when the demand grows and traffic increases, you could upgrade.