If you're both 50/50 in each asset, why not create a partnership now, and contribute both assets to the partnership; where you will be 50/50 owners.

2) Also, is it allowed for proceeds of both sales to be used as down payment towards 1 single asset?

Valuation of the asset condition is even more important than calculating returns because your calculation of returns comes after asset condition valuation. 

Generic online contracts or other one-size-fits-all documents can contain illegal provisions under state law that may cause legal and financial woeWisconsin Lease Laws In accordance with Section 704.44 of the Wisconsin Statutes, a residential lease can be considered void and unenforceable if it includes any of the ten invalid provisions outlined in the statute.

I had to figure that out myself as well a couple of years ago haha as already mentioned, first things first, make sure you feel financially stable and secure. 

Project size and asset class can greatly impact lease up schedule.

You will also learn from others which operators they like or don't like, which asset classes are going well, diversification strategies, standard terms and more - and most of all you will have other like minded individuals to consult with who are on a similar journey.  

We lived in the house for 2 years, and as part of our long term strategy, we wanted to keep the house, rent it out (essentially have someone else pay it off for us), and keep it as an asset.

@Minji KimRecommend you first figure out the property Class you want to invest in, THEN figure out the corresponding location to invest in.Property Class will typically dictate the Class of tenant you get, which is VERY important for stable rental income and low property maintenance/damage.If you apply Class A assumptions to a Class B or C purchase, your expectations won’t be met and it may be a financial disaster.If you buy/renovate a Class A property in Class D area, what quality of tenant will you get?

They also have tools for on boarding investors.There are property managements softwares to help with property/asset management.There are CRMs that help with capital raising and investor automations.I would not focus on automation right now, but on the business of multifamily.