I agree - I'm surprised your surgeon didn't bring this up with you. Normally gastric bypass is recommended for people with reflux.
as for your other questions,
1 . Does GS affect your breathing in any way ?
Haven't heard of this issue
2. is there any vomitation of blood in the mouth after surgery
haven't heard of this - but it seems plausible since it's stomach surgery, so I suppose it could happen
3. Can I smoke my vape with nicotine after GS
we were told no smoking/nicotine
4. Is it hard to swallow (water/protein drinks) in the days after GS
for some, yes - but for most, no.
5. What happens if I miss my Vitamin tablets for a couple of days , will I feel weak ?
a couple of days shouldn't be an issue, but I wouldn't make a habit of it. We have a few sleevers on here who were given the go-ahead to stop taking certain or all vitamins based on their lab results - but it'll be awhile before that kind of decision (might be...) made. In the mean time, you should be taking them regularly.
6. I suffer from Heartburn (gastric reflux)will my heartburn tablets be ok to take after the surgery
yes, you can take heartburn meds, but again, I'm a little surprised you'll be getting sleeve surgery since you suffer from heartburn. Sleeve can make that worse. It's not inevitable - and it doesn't even happen to the majority - but the risk is big enough that many surgeons will recommend bypass instead of sleeve for heartburn sufferers.