Generally, rental activities are passive activities even if you materially participated in them. However, if you qualified as a real estate professional, rental real estate activities in which you materially participated aren’t passive activities. For this purpose, each interest you have in a rental real estate activity is a separate activity, unless you choose to treat all interests in rental real estate activities as one activity. See the Instructions for Schedule E (Form 1040), Supplemental Income and Loss, for information about making this choice.
I actually spent a year and a half working as an affiliate marketer (mostly selling drumming related products – lessons, kits ect). 5 years on and one of my one page sites (which I’ve not touched) still nets me about $150 a month. I won’t be retiring off that but only really now appreciate the reverse pyramid approach to entrepreneurship (working for nothing initially but later being paid without effort!)
Real estate crowdfunding presents a middle-ground solution. Investors have their choice of equity or debt investments in both commercial and residential properties. Unlike a REIT, the investor gets the tax advantages of direct ownership, including the depreciation deduction without any of the added responsibilities that go along with owning a property.
Some people take it automated well before the year is up. When it converts, it converts. If you target the right people and you're able to create the right message that appeals to your audience, you might just hit a home run. An automated webinar often involves the creation of a webinar funnel. That includes, not only the webinar, but also the email sequences, and possibly a self-liquidating offer, and maybe some done-for-your services and up-sells.
In most cases, all rental real estate activities (except those of certain real estate professionals, discussed later) are passive activities. For this purpose, a rental activity is an activity from which you receive income mainly for the use of tangible property, rather than for services. For a discussion of activities that aren’t considered rental activities, see Rental Activities in Pub. 925.

One of the most appealing options, particularly for millennials, would be #12 on your list (create a Blog/Youtube channel). The videos can be about anything that interests you, from your daily makeup routine (with affiliate links to the products you use), recipes (what you eat each day) or as you mention, instructional videos (again with affiliate links to the products you use). Once you gain a large following and viewership, you can earn via Adsense on YouTube.