What documents do they require, what credit scores do they allow, how do they verify previous rental history, etc.?

I ran some quick numbers and would estimate (assuming you have good credit) you could borrow around $415k-$420k, which includes funding 100% of the rehab costs.Have you calculated your expected profit based on selling after rehab and if you decide to keep long term? 

While you shouldn’t categorize all tenants and it’s the landlords responsibility to properly screen, the tenants who reside in better situated housing and pay higher rents are more financially responsible meaning lower rate of rent loss and will generally take better care of the property which combined will result in less time allocated towards management functions if self-performed or more favorable management fee structures if 3rd party management companies are utilized (which ties back to #1, as well).

If the students do not have the income or credit to warrant the rent amount, I would require that they get a cosigner (like a parent or another relative that can vouch for them).

This also includes a few credit cards that are used for business expenses.

sometimes to reduce borrowing costs, I'll use a hard money loan solely for the purchase, and then pay for the rehab in cash or use a 0% credit card (I don't recommend that for new investors!)

Also, your DTI can sometimes be more flexible depending on your credit score or reserves, so it’s worth asking the lender about that.If your DTI is still too high, try looking at ways to lower your monthly payments or increase your rental income.

Check with a few local credit unions as they usually have the best HELOC offerings.

Next year i'll hit top pay and should start bringing in 1.2-1.3k a week. and the year after that i plan to move to linehaul and make about 2k a week.I do have a lot of debt, or at least it feels like it to me. the breakdown being;23k in college debt i got getting a bachelors that i never used across 5 loans ranging from 3 to 5% interest rate5k in bank loan debt i got getting my trucker cdl a at 12% interest rate.2.5k in credit card debt from not having an emergency fund and then having emergencies.

If i can invest it and make a significant better return after tax than paying it down I would do that but in this instance you will never be able to achieve returns that match credit card debt.