It’s saying that you have recovered from Covid and are not contagious but still might test positive on a PCR test, several people have made posts in this group so shouldn’t be too hard to find with the search function
you should be better at guessing games by now, think she means she can’t go to HK from the US so she needs to spend X amount of time elsewhere so she’s not “coming from the US”
there’s been other posts about charging extra for “expediting the process”, which seems to be a very common tactic for charging extra. Sadly I don’t think there’s actually much recourse or the hassle is actually worth it.