Here are some key questions to ask:
1) ask if they are activley Investing @ this time?
2) What level of Rehabs are they comfortable with?
3) What type of properties are they interested in: single family residences, multi family, commercial, multi units, etc.
4) Approximatley how much capital are they working with?
5) How many real estate transactions have they done?
This is probably the MOST important question-
6) How quickly can you close?