After our Plumbers put in our sinks in the Master Bathroom one of them would not drain.

As others have said, from an investor's standpoint, you should be able to find an investment that is improving your financial position and not draining your cash reserves.Sorry for the long post, I realize I'm jumping all over the place but this is just food for thought from another HB'er :)

It's easy to mess that up by not digging deep enough, putting in proper rock and possibly tying to a drain tile (easier said than done), oh and sealing the new hole in foundation properly. 

Try renting it out for a year or two and if becomes too much of a burden and drain, sell it off. 

Upstairs had a legit plumbing leak from old galvanized kitchen drain pipe, that was coming unfrom next door unit.

As others have stated, that $1,000/mo net will be drained very quickly after factoring prop management, repairs, vacancy, tax’s, etc. maybe not repairs for the first year or two since it’d be a new building but they would be inevitable in the future.

I assumed, being the plumber - that he would do so, he explained that we hadn't mentioned this and he'd have to 'send some guys out'. 5 months later and it turns out the waste pipe from the apartment has been draining into our crawl space as no one connected it.

The concrete is leaning towards the house and the garage drain that the washer drains into may be putting water under the garage floor (4 inch drop along a crack by drain), so will probably have to borrow for that work anyway.  

Do I just cut a hole in the white plastic and stick the drain tube from the washer down the hole?

You will highly regret it if you hold onto it because it will just drain money from your account on a monthly basis.