I'd like to own a number of rentals to generate a passive income and create wealth and do a few fix and flips per year for extra cash flow. 

Usually if it sounds to good to be true, it probably is. :)  But I can vouch for Cozy being legit, and I have no affiliation to them other than I'm a customer. 

Not only does it make the house stink, but there's a lot of extra labor involved (i.e. washing/scrubbing walls) whenever it's time to repaint. 

Its your house.There are quite a few drawbacks to bidding at the sale:You usually can not get into the home before purchasing it.You dont know what the person getting foreclosed on will do with the property as you try to evict them if it goes that way.There are lots of people bidding up prices making most of these properties, not really good deals.

Dog washing stations can be integrated into a property designating an area outside the building to wash Fido, or by creating a space within the laundry room where there might be extra room.

The oil tank is in the basement (so no environmental concerns) but I'm wondering how oil deliveries and cost are usually handled in a rental lease.

An entity will need to be done pretty soon if you have anything to lose.Always remember to do the math analysis and try to look at the prospective property or at least have a clause in the sales contract that allows you some time (usually about 15 days) to make a detailed inspection and possibly back out of the deal without a penalty that will hurt you too much.  

@Jim Carson, Never say never but a 50% depreciated national market isn't usually part of the normal real estate cycle.  

With that said, the declaration would note at what point the developer needs to turn over control to the owners - usually it's when 75% of the units are sold.

That does usually mean you'd have to share profits but it is a great way to learn the process from those who have been around the block so to speak.