Here is a list of some questions you may want to ask before placing your offer.

1. Are there any issues we should be aware of?
2. a)Has there ever been any flooding?
3. Any Grading issues?
4. Is there a backflow valve in the basement? 
5. Is the home built pre 1980? Is there clay pipe running from the home to the main sewer at street?
6. Any insurance claims on the home?
7. Is there a survey?
8. Are there any easements on the property?
9. Any zoning restrictions? Part of any escarpment or land authority?
10. Any home improvements completed recently? Is there permits for any of the completed work?
11. Any rental items? i.e. hot water tank, or furnace?
12. Does the seller have a home inspection from when they bought the property?
13. Do you have a list of upgrades the seller has done since they purchased the property?
14. Is there a primary comparable you and your seller reviewed in order to evaluate the property?
15. Specific questions relating to that home. I.e. we noticed...
16. Can you share your comparables appraisal with us? 
17. Is there a price your sellers are willing to accept?
18. What closing date are you looking for?
19. What time can we/ you present the offer?
20. What time the presentation is? I saw the offer registration is 4p. Are presentations in person at the property?
21. What is your offer night protocol? ie. I let agents/ clients know "I will be recommending to the Sellers that they take the best offer (as defined by them).   We will try to stay away from 2nd or 3rd rounds"

Ages of:

Furnace

Roof

AC

Windows
Pool
Pool liner
 

If it is a Condo then make sure to ask these questions.

When will the status certificate be ready?
Is there any issues in the status?

What can we do to find extra parking?
Where are the amenities?