I plan to hold the expense cash until each property has a reserve of $20,000 then I will roll over the additional expense holding to my intake each month.  

Knowing you have a mortgage rollover every 5-years is an encouragement to pay down principal.  

To answer your question MR Worland Currently I have a conventional 401k plan I m wanting to Roll over into a self directed 401k for purchasing some rental properties.

Choose the one that is best for you.See if you can roll over your 401(k) into your IRA. 

There isn't a way to just roll over the capital gains portion of the sale (300k) and cash out on the 100k basis.  

When a lease expired it will automatically roll over to month-to-month tenancy.

I currently have a $500k term policy that can be converted into Universal Whole Life and also significant assets in a ROTH, Rollover IRA and 401k from my last job.

You don't deduct the loss that year, but it does roll over to the next year.  

Fund this Solo 401k (through rollover) from my active employer sponsored 401k.

There also may not be advantages as compared to your self-directed IRA, depending on your situation and goals.Either way, you can likely consolidate the existing SDIRA and new rollover funds into either the existing IRA or a new Solo 401k.