Hi! Welcome!
1) $80k in cash is a very nice place to be. You can start a small LAN with no loans and only borrow from yourself (no interest). Or, you can leverage that $80k and get a SBL from a bank for another $80-$150k using your $80k and the company assets as collateral.
2) $15/sqft/yr is not high. $30 is high, and $50+ is generally ridiculous. Here is the rule of thumb : assuming your lessor is offering a fair price, then you can either have a nice location and spend a small amount on advertising, or you can get a cheap location and spend a ton on advertising to get people to notice your hole-in-the-wall.
3) If you can get a liquor license, do it. Don't worry about cutting out the younger crowd unless that's what you really want to target (everyone is entitled to personal preference, I'm just speaking from the business perspective). The
average age of the self-described gamer is 37 which means that there are a good section of gamers that are even 40+. Do some quick napkin math and see what the larger demographic is : under 18 (12 - 18 = 6yr span) or 18+ or 21+ (21 - 40 = 19yr span).
4)
First read this about small station counts. As for the PS3, if you don't know about it, don't put it in the store. This is not an accusation of incompetence, but rather a point about social engineering. If you (or someone else who is there on a daily basis) is not enthusiastic about the PC/PS3/X360/Wii, then you will not talk to your customers about it as much, they will not become interested, and they will not play it as much. (this also applies to individual games btw)
5)
Here is a nice article by a friend of mine detailing what it takes be a restaurant, and to a lesser extent, serve any kind of prepared food. Snacks and drinks, anything in a package, you're fine. Serve any kind of prepared food, and you need a license, so be prepared. Computer repair would be a much more sensible move IMO.
6) :p
7) Yes. Be up front about who you are and why you are there, don't skulk around. Call ahead and find out who the owner is. A lot of people are very protective of their business model (I've no idea why, none of us are millionaires, but everyone thinks they will be, and very few of us are close enough to compete with one another). Don't be afraid to offer a token amount of cash for their time if they will answer some questions.