@Pat Aboukhaled I would ULS (unit lot segment) the primary house and include a clause in the call option that would prevent them acquiring the DADU.

I would be cautious buying in the saturated areas because there are so many similarly sized properties that price is becoming increasingly the deciding factor. 

Building a solid team is another crucial factor.

There is the inconvenience factor but it might be cheaper for you and your friends as well.

But there are bunch of factors to consider there. 

If a property needs too much work upfront, it may not be the best first investment.4.Factor in property management costs—even if you self-manage.

This will help you understand the qualifying requirements, key factors to consider when purchasing, and how to assess whether a property might be a good investment at first glance.

This reminds me of how Alex Hormozie describes "the value equation"; Experience in this case is the factor that determines the likelihood of achievement. 1,000%Alex Hormozie is one of the greatest marketers not just alive, but ever. 

I just include the utilities in the rent.

Also your permitting process, type or land, grade of land, if underpinning is required will all play a factor into your cost.