Congrats on your weight loss so far! You're doing great!
1) Yes, I get hiccups sometimes when I eat too fast. It hurts! 😢 (my surgery has a VSG stomach. Just with the intestinal bypass bit added that makes it the Loop DS)
2) I do stagger sometimes, but I also have arthritis in my knees, hips, and back so I always attribute any staggering to that. But, honestly, you've lost more than 25% of your weight. As the above poster mentioned, your center of gravity may be a bit off and you should be able to adjust over time.
3) Well, I was a 34 in jeans when I was at my highest weight (389 pounds) and my shirts were 6xl. I had clothing from about 15 years before when I was a 26 in jeans and some shirts from high school that ranged from 3xl-4xl so I put off buying clothes for quite a while lol. I went from those 26 jeans straight into an 18 (that I luckily didn't have to buy because my Mom wore this size so she just gave me a few of her pants). I also bought a few xl shirts around that time too. They were all on sale lol. Then I waited and bought 14's when the 18's were sliding off. I also bought a bunch of shirts since I figured I was close to my goal weight at the time so I bought a bunch of larges. I'm now in a size 12 in jeans and wear both medium or large shirts depending on the fit. Personally, I'd say buy a few things off the clearance rack if you can't stand how big your clothes are, but since you'll probably grow out of them pretty fast, don't buy a whole lot.