The next neighborhood, Irvine is at least 700,000+ or even higher with decent size SFR (and I only talking about 1600+sqft).

WIndow size is fine.

Tenant may plant the beds adjacent totheir dwelling to their liking, but only with those plants that are ofappropriate size and type for the beds. 

So if you're making one room bigger and another smaller, you'll have to increase the size of the radiator in the large room and decrease the size in the smaller room. 

It looked pretty nice and had a good sized yard, driveway, and garage as well, if I remember correctly. 

In the few area's I looked, they all have multiple homes for rent, some more than others due to size/population of the area. 

Solid wood slab doors are more than sufficient, and not that difficult to get to fit standard sized doors -- would assume that is a 36" might cost you 120 bucks at a good hardware or door specialty shop.

Since you mentioned that it is for a long term hold, I would also consider the LLC route despite its costs - if the size of your deal warrants it.There are certainly risks (but that's what insurance is for) - but you can just own the property as tenant in common (so you'll be under title). 

Large and medium size banks often sell their loans to the secondary market (Fannie may, Freddie Mac Etc.)

The trade-offs are it can be harder to find tenants.Generally for a SFH rental you will want a property that is about average in size and lot size, if not slightly below.