It's very likely that the lot in question IS already zoned Commercial but an employee of the city made a wrong assumption when mapping and recording about a decade ago.

Considering they still own the property AND still have tenants, are they not violating the law by not having a valid CO?

You should also have a comfort level with your CPA.

If you're looking for appreciation: neighborhood quality, school ratings, crime levels, population changes, renter/owner occupant ratio.

There's a plethora of information on this website, as well as countless people I've personally met in my investing career that can truly take you to the next level, or to any level that you so seek.

Are they on track with current dues levels and reserves to meet the capital improvements required?

It need s a on of work, floor leveling, roof replacement (rafters and all) a new bathroom to be rentable.

Most have a tenant rep broker they use and connect you up with them.Cap rate is usually tied to location ( urban,suburban,rural), location and quality of the tenants ( national, regional, mom and pop), and terms of the lease ( primary lease term in years, level of lease guarantee, rental increases, any termination rights, disclosure of sales, restrictive use rights, co-tenant anchor clauses,etc.).You need a void analysis from a landlord rep leasing broker.

Basically the textbook stated that, there is a new law in New Jersey, that if you try to sell a co-op, for the same amount or less then your investment, but aren’t successful after 4+ months on the market, then you can rent it out, regardless of any lease bylaws the board of that co-op has for renting. 

That would include you or them acting as a third party facilitating a real estate transaction between two other people.If you are only buying properties for yourself to flip or whatever, and these appointment setters are your actual W2 employees and not 1099 contractors, then you are probably OK.If you're a wholesaler and don't intend to take possession of the property, well that could be completely different.As always, I would advise spending a few bucks to talk to a real estate attorney on matters like this.