I'm interested in buying property in the US for flipping after renovating. Would really be grateful for any advice.

Buying REO or foreclosures is better?
When buying these do we get to see a report of a survey about the exact condition of the house. The things you can't see in pictures Ie. plumbing, wiring, internal etc. ( to avoid surprises later which add cost and time for repairs).
Is it better to hire 1 contractor to do the whole renovation? Do they supply the material or do we need to buy separately? Ie wooden floors, paint, tiles etc.

How many bedrooms in a house for best flip potential?

How to know where the best location is? Is there any info online about home buyer's index/statistics in particular suburbs?

Thank you in advance for any input or feedback.