1. Kegging for storage is not a good plan if you can serve from brights. Kegging a little for long term aging is fine.
2. I think you are under estimating how much work there is and the amount of training and supervision people need.
3. If the paperwork isn't done, you cannot legally make beer.
4. It will be good to be busy, but that's a lot of beer you need to make. With 125 seats, how many beers per seat per day do you think you'll sell? 1? 3? 10? Do some math - for example let's make up some numbers . . . if you will be open for 8 hours a day, and seats turn over every 1 hour, and the average patron drinks 1 pint, that works out to 125*8*1*1, or 1000 pints per day. That's roughly 4 bbls of beer per day, 30 days in a month means 120 bbls of beer per month. On a 7 bbl system you need to brew 18 batches per month to have enough beer. Each batch takes 2 weeks, so you need 9 fermenters to handle that amount. 7 bbl of beer is a huge amount from a homebrew perspective, from a professional perspective it is tiny. Maybe my numbers are wrong, maybe you'll only sell half that - you still need 9 batches per month, and 5 fermenters. The amount of beer you will sell to get away with 4 @ 7 bbl batches per month works out to ~231 pints per day. That's less than 2 per seat, which makes me question why you would make beer there in the first place, you're not making enough money on beer to justify the space and expense.
5. You think you can brew 4 batches in one day? Or am I reading that wrong? Just consider how much power it will take to heat enough water fast enough to do 4@ 7 bbl batches in one day. Are you planning on brewing with extract? Because milling takes time, mashing takes time, transfers take time, boiling, chilling, etc. Problems also take time, and there are usually problems of one sort or another. Equipment breaks or doesn't perform as expected, etc. And if you are brewing 4 batches in one day you need 4 fermenters, which takes up space, and hopefully once they are done they won't sit empty until the following month.
6. Until you start driving the 2 hours per day for 2 hours worth of work and start to hate it. And if you are looking for incredibly lucrative work, a brewpub is not your best bet.
7. It's good to have goals, I hope you achieve them.
I'm not trying to dissuade you, just trying to give you a realistic point of view so you can make a good decision. I think Sean is right, a 7 bbl system for a 125 seat place is a full time+ job if the place is going to be successful selling beer.