My first tourney

Have my first tourney coming up in 2.5 weeks and had a few questions. My university is organizing it but it's open to other schools in the area. Our club mostly learns BJJ basics from a great brown belt 2x/week and a black belt 1x/week. They're great guys but I don't necessarily feel comfortable approaching them with really specific tournament legality, strategy, and social norm questions that I'm hoping y'all can help me out with. So here they are:

1) This one's a total confused newb question. The tournament website says you're guaranteed 2 gi fights in the morning of the tourney and 2 no-gi fights afternoon. Hypothetically, if I won all 4 fights, how many more match would I have? Is there a set or ballpark number? Or do you get only 4 fights total, regardless of whether you win or lose?

2) What should I do about my weight? Here're the relevant categories:

* feather: 141-154
* light: 154 – 167.5

I usually weigh 165 but due an injury 4 weeks ago I've lost weight and am around 158. I used to wrestle so I know how to cut weight, but which is the best strategy: to try to get down to 151 (+ 3 for gi right?), lift weights to beef up and gain a couple pounds of muscle over the next two weeks, or do what I usually do for cross-training: climb and cycle?

3) General strategies for pacing yourself? Do you go all out in each match? I have no experience with the gi and have been training no gi for a month total (have been recovering from a separated rib for the past 4 weeks) so I'm thinking I will go fairly hard during the gi matches (with few expectations of winning) but save more than enough energy to go all out in the no gi matches, which is where I think my comparative advantage is.

4) What 10pjj stuff is illegal? For the gi matches, they're following IBJJF rules, which I read a week ago and found to be a bit convoluted. The tourney also specifically disallows "bicep/calf locks, Heel hooks, Neck cranks, and any Leg/foot locks that twist the knee." Again, I'm a newb, but I'm assuming this means no twister submission, no arm crush from spiderweb, no duda from rubber guard, etc. What I'm unsure about is whether something like the Electric Chair submission from half guard would get me in trouble. It's technically not against the rules right? A blue belt warned me today that it's the ref's discretion so if a submission I apply looks like anything banned, I might get forfeited. So should I avoid groin stretch submissions? This would take away a lot of most of the remaining (legal) twister side control game, which I haven't fully incorporated yet anyway, but want to.

Are there any examples of 10p leg/foot lock submissions that don't "twist the knee," i.e., that I could use in this tournament?

Damn! Those are all good questions and hard to answer. Personally, I'd make the cut to the lighter weight if its possible. If not just follow your normal weights routine and don't worry about adding muscle. Its not going to make much off a difference in a few weeks. Instead focus on building core strength. You can make great gains in just a few weeks doing core excersices.
As far as what is legal and what is not, it differs from tourny to tourny. I find talking to refs or fellow competitors when I get there is very helpful in clearing that up. If you are that advanced in your game, maybe bump up a lvl so you can use all of your game. Otherwise you are going to have to make due with what you can use. Best of luck to you and hope this helps in some way :D