1) Founding some SaaS or ebook and throwing money at marketing - $30k
2) ETFs - $120k
3) Stocks $50k
4) Any other ideas?
The goal is to generate passive income but also be able to earn more once I decide to have a family etc.
Not trying to be difficult or ask you tons of personal info but without knowing more it's difficult to get solid advice.
I'd personally recommend you talk with 2 or 3 financial advisors and see what they tell you.
Personally using 200k, I'd likely put 50% or so into a reasonable growth fund and let it ride. And I'd take the remaining and likely leverage it to fund your passion where you can make money. In my case it'd be either real estate or some Business adventure. I'd possibly even look at franchises as a return of $80-100k/year out of a manager managed store (e.g. You don't work there) is a quick way to grow your wealth. As you can continue to add more stores or different ones.
You could also invest more and work to get a letter of credit against some percentage and then use that money to finance your ventures. Again something a solid financial advisor can help you with.
$200k isn't a lot but it is a very nice savings (congrats) so being smart with it can responsibly grow it in just a few years. And done right you could wind up with enough passive income not to need to work for anyone and just focus on what you want to do. But getting 10% returns a year on 200k isn't good enough so to leverage it is the way to go in my opinion.