It depends whether the supplier is willing to send them as a gift.
Regarding taxes, you can't get into trouble because all tax information is confidential. E.g. Drug dealers still have to pay tax, even though their earnings are illegal. But because the records are private, they can't be used as evidence for prosecution.
It is illegal to sell replicas Nikes in the US, although that doesn't necessarily stop people from doing it. It's also important to distinguish between no-brand goods that look like the real thing, and replicas that are deliberately deceptive (e.g. have a brandname or logo). It is the deliberately deceptive items with a brandname or logo that are illegal.
The main risk is Custom's seizing your goods when they are imported, however, you can also be reported by other eBayers if someone notices you are selling fakes. I'm not so sure if Craigs List has the infrastructure in place to deal with removing listings for fakes, but we recommend staying well away from replicas. Companies are gradually cracking down more too, so pressure is increasing to penalize anyone who tries.