I've also got a buddy that's a commercial lender that's advised me that he'd be able to finance 80% of any deals that I'm interested in (depending on the strength deal obviously).My question really pertains to that remaining 20%. 

I would just write up a new lease with the remaining tenant for however long is remaining on their lease. 

However, you are correct; if you tie up a property and cant deliver they will assume you are a bozo and ignore you from there on.

The remaining 200 sqf I want to make a “loft/family room” that would be at the top of the stairs and lead into the master; also have beautiful views.

In the event that we would purchase a property, the standard 2.4 percent commission comes from the listing agent, and I'm on the hook for the remaining 1.6%.

It is also possible to structure an Improvement 1031 Exchange whereby your Qualified Intermediary (exchange company) acquires and holds or "parks" legal title to your new replacement property so that you have the rest of your 180 calendar day exchange period to use any remaining funds in your 1031 Exchange to complete improvements as part of your 1031 Exchange. 

I've been following BiggerPockets content for a while and am ready to bombard y'all with questions 😁Here's the first one:I've read that it's a good idea to purchase a rental property under an LLC to remain anonymous to disgruntled tenants, separate your business and personal assets, etc.

I have done some Walgreens deals recently where the remaining lease term was 6.5 primary years left but credit union gave 10 year fixed rate loan.They felt with low cost per ft rent and strong sales shown that Walgreens was going to renew the option as the location was highly profitable.

Did you have the property tied up with a contract?

To make money, the property must remain occupied by a tenant who pays all the rent on schedule and takes care of the property.