Everyone has a different risk tolerance, so bear that in mind and choose your path based on yours. I will say your questions sketch a risk tolerance that to me is extreme in both directions.
1. The BiggerPockets lease agreements have undoubtably held up in court. SO many people use them that if they didn't, we'd know it loud and clear. Don't invest an unnecessary $1900.
2. View your properties as a business. Rent at market price. You'll get the best candidate pool for the vacancy. Yes, you may be able to go high, but if you miss a week, two weeks, or even a month trying to fish for more rent, the cost of vacancy will out-weight getting it filled quickly at the lower, competitive pricing.
3a. Your expectations are way too high. There's typically a reason folks are renting and marginal credit scores and low cash-on-hand are among the top three. If a renter can come up with three-months worth of cost, they can probably afford to buy a starter home. Moreover, you'll want to look at local laws if you ask for 2-months deposit, as that may not be legal, but even if it is, you'll extremely limit your tenant pool by requesting that much money. It's unnecessary if you find good renters anyway.
3b. You should never have issues if you aim for 650 or higher, especially because the most important elements of a tenant are going to be employment history and eviction history. As long as your tenant has a history of strong employment and no evictions, with a decent credit score, you'll likely be okay. I do focus on previous rent experience too. But if you want a 740 credit score, you'd decline me! I simply move too fast for banks, and I'm smart with debt, so if I can ride an interest-free credit card balance for 18 months, you bet I will. But that all hurts my credit score, which is hovering around 700. That said, I've never missed a payment, failed to pay in full, or put myself in a position of debt where I can't afford to pay off in full.
Be smart, but don't get greedy. Best of luck!