Hey Jeff! Welcome to the forum!
- I think the standard "best practice" is to start an LLC, but it's not a requirement. If you already have an LLC, you could start with that or form a new one. Honestly though, if you feel bogged down by this one step, don't let it keep you from moving forward and taking action. There's no rule saying you can't get started with your personal name and come back and form an LLC once you've proven the concept to yourself.
- That depends a lot on what format the list comes in (and there are a lot of different formats these can come in). You're right, some of them are VERY dense and hard to get through... but if you can do it, you'll be one of the few who actually went so far as to get access to those motivated sellers.
- I would expect a handful of angry responses (and if you send them to a voicemail greeting of a virtual receptionist, you'll never have to talk to them anyway), a handful of people who call and hang up, and a handful of people who happily accept your offers. In terms of the quantity of each, it depends a lot on how much mail you send out in total, how well you've scrubbed your list, and how good your offers are.
I'm glad to see you've found some value in REtipster, that's really encouraging to hear!