Anyone can set up LLC in the US, that is not an issue. The problem is to be able to open a bank account. If you want to buy an existing LLC and hope to get their bank accounts, please expect as a minimum a personal interview with the bank (I am just going through this process myself for my client). You will also need an ITIN -
Individual taxpayer identification number (ITIN) | Internal Revenue Service. Also if you plan on doing business within the US, do not open a Wyoming LLC as it likely will have no standing in the other 49 states. Wyoming LLC has its uses, but not when you try to do a business in the US. Hope this helps.
Cheers