@Eric DeVito congrats on the sale! Appreciation can truly build wealth quickly. Here are my answers to your questions:
1) Start by reading David Greene's book on Long-Distance Real Estate Investing. It will give you a good foundation and get you started.
2) Real estate agents will be able to help you with this - just make sure you talk to a few and find one that works with flippers.
3) Talk to investors in the area. You can also call contractors in the area to get ballpark figures. Not all will be willing to give you blind estimates, but some will and it will give you a good starting point with the rehab budget.
4) Be clear on your scope of work to avoid mistakes and have a good team - good contractors (use Facetime often to check in on them), good agent / property manager / supervisor that can check on the property for you and send you pictures of the work. David Greene's book goes into all of these questions in detail.
Hope this helps - best of luck!