Permit just expired but I am to submit a certificate of occupancy application, I have the ez sign form as well but kind of stuck on the whole process.

You have to decide on your criteria and then run a pro forma analysis on each property to determine if it meets your metrics.Once you do that 50 or 100 times, you'll start to see patterns and will know intuitively if a deal might work for you.BP has a great book on investing in rental properties by Brandon Turner.

However your situation becomes a trickier case study since these properties first served as your primary residence which could provide additional benefits form a tax perspective not available to an owner of investment real estate and nobody has a crystal ball and knows the property with certainty will transition into an investment property. 

The person who served the notice must complete the Declaration of Service form as follows:a) Indicate the date the notice was servedb) Indicate the type of notice servedc) Indicate the manner of serviced) Sign and date the declaratione) Indicate the place (city) the declaration is signed4.

I understand LP is preferred over LLC due to avoiding double taxation, but if I plan to stay in the US and keep the money in the US, do I still form a LP?

Do you form a new LLC/entity with each new property you buy or do you have one LLC/entity holding them all?

Again, others might feel differently here.3) property level due diligence: (takes seconds to weeks per deal): here is where I drill in with the low-level details.a) pro forma popping: I examine all the assumptions, and see if they are overoptimistic or not.

Or, actually form a C Corp entity? 

i don't do/invest in residential real estate but perhaps it would be possible to learn SFR by getting job in property management, also get RE agent license, then once you have learned a fair bit, form a syndication with yourself as GP, get your college friends, their families, and anyone you know to invest as limited partners, then buy a rental house for cash, and you take 20-25% equity and provide the property management for a % of the rent, whatever is industry standard.

@Ashish Acharya and @Dmitriy Fomichenko  thanks for the responses.Currently, we are using the schedule C plan to fund the solo 401k, however, income on Schedule C gets taxed as ordinary income, which is a huge hit.Follow my thought process here for a moment:I form a separate LLC taxed as an S-Corp, lets call it XYZ.