Hi @Blaine Cox To answer some of your questions directly - you can set the loan(s) up however you'd like. In other words, if someone lends you $100k, they can provide all of those funds at closing or some at closing and some during the rehab, etc. Repayment can be structured however you like, too. You can make principal and interest payments or interest only payments. You can structure payment frequency too. So payments can be monthly, quarterly, or one payment at the end. I guess it depends who you are borrowing from and how much. But, IMO, I'd offer to make monthly interest only payments. For example, this means, if you are borrowing $100k at 8%, the total annual interest would be $8000. Therefore, $8000/12 = $666.67. So that's what you'd pay your lender. Also, the lender can charge points or not. 1 point = 1% of loan, so on a $100k loan, that would be $1000. The point, based on my experience, is usually paid up front (at closing). But, you could ask your lender to pay this at the end.
Definitely handle all of this formally. In other words, make sure there is a promissory note and mortgage (or deed of trust). It depends on where you live. So having an attorney get involved is likely. That investment (to create the docs) is usually covered by the borrower. How much that will cost will vary greatly, so it should be less than $3000...but it really depends on the attorney you find and the loan terms you want (i.e. lawyers charge by the hour, so typically each email, phone call, meeting, cost money).
I've been a lender on a decent amount of deals, but I've never done a revolving line of credit. I'm not sure I'd see the value. I've worked with repeat lenders and typically what happens is that once a deal closes, the borrower already has his next project lined up and we roll right into that. So it's kind of like revolving credit.
Finally, you do NOT need to buy this property in an LLC or other entity. If can definitely be in your name. If you are just starting out, I would not get too bogged down in your personal name vs. an LLC. Using LLCs or other entities have some tax advantages and protect you from various things, but there are also advantages to doing things in your own name. I would recommend a project or two in your own name before spending the time, energy and money to setup an LLC. If you already have an LLC, then it probably makes sense to use the LLC.
One final thing, if you use a private lender, make sure when you pay the loan off that the mortgage (or deed of trust) gets satisfied. This is an official step that must be done with the county.
Anyways...I know that was a lot. I'd be happy to chat further if you want. Just DM via BP and we can chat! Good luck!