I have booked TK to Da Nang for a New Year holiday – booked via a travel agency, but the routing is also sold on the TK website

We fly OSL-IST-SGN-DAD, where the last SGN-DAD leg is with Vietnam Airlines

Vietnam Airlines is part of Skyteam – how does it work with the Star Alliance Gold benefits?

On the trip to DAD, do we have lounge access in SGN?
On the way back, do we get priority check-in, fast-track and lounge in DAD?

How would possible upgrades work? Flying on two expensive economy class tickets with two *G cards, gives a glimmer of hope for complimentary upgrades