In those cases the 100k to 300k they own a slice of a much larger property in an area they could not buy and purchase on their own.

were I see a lot of BP folks stumble is thinking they should get the bigger slice of the pie than the money... and then they never do a deal and can't figure out why

Slice off a piece of drywall (just the top paper, not all the way through) about the size of a business card right next to the spot that you will be repairing and bring it to Lowes or Home Depot.

I've seen a few porches demo'd and if you strap a good chain to one on a strong truck, you can usually pull the entire structure down without hurting the house (assuming you sliced the roof first). 

No matter what way you slice it, your max LTV to refinance a SFH investment will be 75% with Conventional financing.

I have only a slice of an answer for you.

MFRs are a bit risky no matter how you slice it.

Bank would want to see forward commitment from tenant going in and also want to see zoning is approved with site plans before closing on the land.If building is older could be more costly to take down.If you are talking a bigger mixed use or multiple tenant type building you will need to bring in a more experienced joint venture partner where you get a small slice of the the deal and learn how they do it. 

Syndicators make money by doing volume and taking slices.  

If you assemble a team, you have a professional PM so tenant selection, maintenance etc is taken care of, but you have to manage lots of moving parts, and give a slice of the pie to each member of your team.