However, in most markets I would assume an additional full bathroom would not only command higher rent, but would increase the equity and appreciation.

It seems like there should be sellers that would be willing to take their equity or at least a portion of it in trade for bitcoin.

Here are a few high level thoughts for you as a beginner:-Don't lend in second position-Don't do deals with new investors-Don't experiment with new strategies, even with experiences investors- ie, don't jump in to a first development project with someone just because they've flipped 20 houses. 

Some positives and negatives to evaluate. 

My plan is to maintain the status quo and benefit from annual rent increases and equity gain as the tenants' rent covers the mortgage.

My plan is to maintain the status quo and benefit from annual rent increases and equity gain as the tenants' rent covers the mortgage.

Maintenance/cap ex, insurance, if a rental PM, bookkeeping, misc.The fact you have a loan means 1) leverage 2) equity pay down.In addition, there are tax benefits.So I will do some rough underwriting as an OO non-rental at 95% LTV (because FHA has some undesired consequences that make the 1.5% difference in LTV worth avoiding the FHA).equity paydown: 20% (using OP interest rate at 95% LTV and not counting closing costs). 

One has no mortgage, their other has a HELOC for around $20k remaining and is coming to its 10year term that was established before placing with LLC.My predicament is how/best way to pull equity out of either property for a down payment for the 3 family that is valued around $450k.

@Robert StephensonYou’re in a great position!

I've got the idea to more positively incentivize my tenants to pay rent by the idea expressed in the following example:- If they pay any later than five days late, they pay base rent ($1,000) + fixed late fee (e.g., $150)- If pay on time without autopay, they pay base rent ($1,000) + "manual payment fee" (e.g., $25 or $50)- If they use autopay for timely payments, they pay just the base rent ($1,000)In the above example, you see that a discount of $25-50 was applied in the case that the tenant chooses to setup autopay to schedule on-time payments via a given PM software.Please let me know if any software comes to mind and also any feedback on the positive incentive idea.Thanks in advance!