Let your son spend the money, time, effort and resources to hire superior legal counsel and negotiate an acceptable solution.

What I can say is to have a strong call to action like...Give away some content...Give away useful tools or resources. 

Then I pull in the energy and water cost to run the building too, which puts me right around the 50% rule I suppose.  

This site will be a good resource for you to network and learn a tom from posting and the pod casts.

Chimneys are energy robbers,,,do you let your windows open all winter?

Depends on your resources and experience.

Be sure to check out “Learn” for all kinds of useful resources and free how to guides.

There are plenty more resources you can find under Education from how to's, blogs from our experts and podcasts.

.#3 is fairly passive if you have a good turnkey company, good location and a good PM.Of course #4 is all you although you could partner up with someone else.So it comes down to your goals, the level of passive vs active investor that you want to be, your resources(Time , Money, Experience).Your choices will depend on your goals. 

BP is full of resources.