Great stuff! The only thing I would add is the tendency for a newbie to think stuff like, "Yeah, it sounds like a PITA, and it may be, but no problem, I'll just hire contractors and a property manager and they will take care of everything for me. Problem solved."
I cringe every time I hear this sentiment, because I suspect that is a newbie that's fixin' to get taken to the cleaners trying to outsource jobs they have no experience or knowledge in. Aside from the financial reality that a PM will consume over 1/3 of your cash flow (~15% all in with all fees included of GROSS rents, which is likely >30% of NET), managing a bad PM is MORE work than managing a good tenant yourself ... a vast majority of PMs are bad (PMs and newbies will argue otherwise, but this has been my experience) ... if you buy quality properties in quality locations (see Sales part in OP) and then screen your tenants, then most tenants are good.
I would also hope that this post would dispel the common false belief that REI, at least as far as owning individual properties, is or even should be a passive investment ... it is not, it is starting and running a business just like any other. If you build and grow your systems properly, then it CAN become more passive over time, but not completely passive and certainly not passive at all as a newbie starting out. I'd argue that Jenna Jameson's business is more passive than a newbie starting out in REI, and more profitable and she may get f#%ed less than a newbie landlord too :)