and was wondering if anyone had any recommendations for brands, online stores in the U.S. etc. If there's anything in particular I should look for or avoid when buying boots/booties for her that information would be greatly appreciated as well.

Thanks! 

Oh, also wanted to add she needs these boots/booties to protect her feet from the snow and frigid temps when she goes out.

Any recommendations for sweaters would also be appreciate...must be a pullover, if it's Velcro she can undo it and shimmy out of it, lol.