The repair guy is suggesting to replace the flooring of the bathtub because patches would crack in a week or two.

If the contractor has no Insurance you are more likely to be drawn into a suit by the injured party,3. an employee of one of the contractors is injured on the job site.  

He suggested spraying enzyme remover and/or 50/50 mix of white vinegar and water. 

My suggestion is to use your own cash to do your first couple make sure you work out the kinks then you can leverage with private money HML or find that unicorn sub to deal.

There is far more prep, detail and care that goes in to doing a decent job and it's super time consuming.

I've heard of mentees who started cleaning up construction areas on a flip at the end of each work day or picking up supplies at Home Depot and delivering them to the job site.

That means we've gone through all the horror stories, scammers, folks running off with money, shoddy work, etc.So you'll probably find few, if any, folks willing to hand those relationships over.My advice would be to test folks out on small jobs and work them up to doing larger ones.

Any thoughts or suggestions are GREATLY appreciated.

They aren't too bad if you automate things.As others have mentioned, reliable cleaners that do a good job are critical to your success.Changing regulations, saturation and a slow economy (like now) can cause you hardships.

They think they can save money, but they end up spending it by taking too long, doing the job wrong, etc.