Okay, so can somebody help me with this one:

I will be arriving at SGN on SQ from SIN, and connecting 4 hours later on VN to REP for one week. Then I will be flying from REP to HAN on VN for a week in Hanoi and Halong Bay, on a cruise. Then flying HAN to SIN on SQ back to LAX in SQ F.

Am I correct in assuming that I wiill only need one entry visa for Hanoi entry (and no visa for SGN international transit)? Is connecting at SGN international simple?

And, in SGN am I correct in assuming that I will be arriving and departing from the SGN international terminal and will stay airside the whole time? All of my bags will be carry-on.

And, will my Star Gold level allow me into the lounge in the SGN international terminal even though I am flying VN Y?

Thanks!