It has been hard to find good and reliable contractors to do repairs and emergency service calls.Anyone has good reliable handyman/plumbers/carpenters/contractors that can refer to me.Thanks in advance

This would buy you time to do the repair and while you figure out the tenant issue. 

I would like to buy properties all-cash from motivated sellers with some to no distress on the property, and then rent them out under a property manager after repairs. 

If the unit is damaged because the leak was allowed to continue, I would charge the tenant for the additional repairs required.If tenants have such obvious lease violations, there is a high risk of additional problems down the road.

Once repairs and rehab done the value goes up to market value.

Banks have similar procedures. 

Historically though condos don't bring much equity but do bring high turn over, repairs, evictions and fees....this  means more risk. 

I wrote a BiggerPockets blog post on how to find comps and calculate the ARV of a potential deal: https://www.biggerpockets.com/blogs/8814/68395-how-to-find-real-estate-comps-and-calculate-after-repair-valueHappy to answer any questions about that blog post or the process in general.As far as finding potential deals, those are slim on the MLS and you'll get the largest spread for your buyers by looking off-market. 

We now had trouble several times now with contractors not pulling permits, delaying repairs and costing us thousands of dollars in the process (even if specifically written in the contract).

If the problem was repaired I am not sure you have a legit complaint.