For tax purposes I made my principal residence 50% and rental investment 50%.

Since we are doing similar projects I'd love to chat and compare notes and see where we can help each other out with GCs and sub contractors. 

I currently have a few properties, and with the market appreciation in the DC metro area, I have about $100k equity in each property I own (four total, nothing compared to what I read on here), and as such I want to continue to build a buy/hold portfolio, but at same time I'd also like to have some money available in case the market takes a turn, in order to be able to make some moves.

Complete exchange all is well.The problem with all forms of reverse exchanges is that the relatively complex structure causes them to be relatively expensive compared to a regular exchange.

The  purpose of your contract will be to identify the price the seller is willing to accept, a deadline, and ensure that you can't be squeezed out.

There's a property in my radar that seems to be inflated in property tax value comparatively to other surrounding multi-families.

If the partners agree to specially allocate one item (for example, capital gains) 80/20 for economic purposes per SEE safe harbor, the corresponding tax amounts must also be allocated 80/20.However, IRS has a framework that can reallocate the partnership items based on the “ partner's interest in the partnership” if IRS determines the method of sharing the partnership items lacks the “Substantial Economic effect” (SEE) To meet the SEE, there are strict rules to maintain meaningful capital accounts including Deficit Makeup Requirement for those accounts.With the requirement, the partner must at some point contribute sufficient capital to eliminate the deficit, and the partner has the burden of the loss that partnership has and the allocation of the partnership will be respected by the IRS.This is a very high-level summary of the rules and is not comprehensive. there are many exceptions as well.Since the substantial economic effect, safe harbor allocation rules are complex and requires considerable additional recordkeeping, it's easier to follow PIP standard. 

I think your purpose for getting into real estate is great!

The sole-proprietor LLC will be pass through for tax purpose anyway at the end of the year.  

I’ve run a comparative analysis so I have a good idea of what the ARV will look like when it’s all rehabbed and ready to sell.