Also, based on the new regulations (1 of the 2 units must be owner-occupied), how do you think this will impact the home's value?

Too often we see Landlords keep rent down to reduce headaches, only to find out later that they can't raise rent due to rent control regulations. 

My question is, can I use one of the separate parcels as collateral for a construction loan to build a multifamily on it (of course adhering to zoning regulations)?

Understand Local Laws:Familiarize yourself with local landlord-tenant laws to ensure you comply with all regulations.

Quote from @Heather Rummel: You can manage it on your own, but it takes a lot of work to educate yourself, particularly in the most heavily regulated corner of the world.I would start by calling around to property managers in the area for help.

The other 1% are constantly reviewed by licensed Realtors, large wholesalers spending $20,000 monthly for marketing, numerous platforms and services selling leads, fix n flippers, syndicators, investment funds,  and “opportunistic” buyers such as myself with millions of dollars in cash to close any discounted deal in less than 48 hours, if need be.  

I'm one year into being a landlord, and I loved it for about the first six months--in spite of numerous challenges.

Start by checking into regulations.

For all loans, amongst other things, I have a recorded Mortgage/Deed of Trust, Promissory Note, and Personal Guarantee in place.Yesterday, out of nowhere, my bank reached out to me and asked me if my business was regulated. 

I'm not saying it always turns out bad, but there are numerous issues that can arise that are not worth the arrangement.