The few individuals investing in real property in a small way were few and not organized into any recognizable grouping.In 1957 Bill Nickerson’s book “How I Turned $1,000 into One Million in Real Estate in My Spare Time” was published.  

@Allen Moore -Hi - I'm surprised no one has responded. 

The main downside is the loan limits for a house with ADU match a single family, not those of a duplex (which is higher).

I spoke to a gentleman yesterday who put 400K into a four unit in the city and his first tenant in the one unit bounced their first month's rent and security deposit checks.

So depending on which of those you see as a benefit, you'll likely prefer one or the other. 

I will be doing a pretty large renovation in one of the units, and mostly cosmetic reno in another unit, so i'm wondering what the best way to go about dealing with any potential lead issues in this case.

I’m going to move forward with just one and am currently exploring loan options.

However, here are a few general suggestions that might help:Since you’re looking to offset rental income and don’t qualify as a real estate professional, one strategy could be to consider any capital improvements you’re planning in the near future.

Are you tackling multiple properties at once or one at a time?

One is the order of possession and the other is an award for the monetary damage.