Wholesaling is hard but you just need to understand your buyers they are far more likely to be flippers so you need to evaluate the deal on that basis more than as a rental, although there are buy and hold investors in SoCal. 

One big upside is that the mortgage will be evaluated based on the performance of the assets and less so your personal financial situation.

Meanwhile the person in charge can also help with me with finding and evaluating new deals.

Since investors evaluate many projects which don’t work out for the contractor, the contractors usually become very reluctant to serve as your budgeting agent.I recommend finding one contractor you trust well and keep working with him/her.  

Macro environmental shifts SHOULD impact micro evaluations.

You can know the formulas on how to evaluate deals perfectly but if you don't know your specific market, you wont know what numbers to plug in the formulas.

However, while I was evaluating to replace or repair the roof ($200 for repair) as I have to pay $3k from my pocket for a replacement.

Go out & take a look at any interesting properties and start evaluation process6.

A general overview of how to evaluate if bringing in homes will work for your park and then how to execute.

This will help you get familiar with evaluating opportunities quickly.