The vast majority of my investing is in retirement accounts and won't be tapped for income until I reach at least 59.5 years old. However, I have a very small taxable investing portfolio (less than $5k) with Ally Invest where I invest in a handful of stocks that I value. I do not use the earnings as income – I simply hold these stocks. But I have an unrealized gain of $340 from this year so far.
You don’t have to invest individually to take advantage of dividend paying stocks (i.e. investing in an ETF like DVY, which currently has a 3.16% dividend yield – almost 4%). And while your math is indeed correct, there is more to dividend paying stocks that just the math. The reason the companies pay dividends is typically because of their underlying strength, steady growth, etc. These companies can be good investments for the long run. As such, it might not make sense to sell.
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.
Online courses have exploded in the past five years. Experts and creators can now create video courses to teach others their craft. A course can be about anything that people want to learn. Friends of mine have created courses and say the amount of effort is similar to writing a book. But once its done and starts to sell, it’s a solid passive income stream.
Another way to generate passive income is to invest and be a silent partner in a business. This is very risky, but with risk comes the potential for high returns. For example, several years ago both Lyft and Uber were looking for private investors to invest in their companies. Today, they are worth billions - but you as an investor would only reap that benefit if they go public via an IPO, or get acquired. So, it's risky.

If retirement is a goal of yours (and who doesn’t want to retire someday?!?), it’s important to learn how to start investing. In fact, funding your retirement accounts should be at the top of your list. While these accounts won’t help your immediate situation, by stashing cash now, the residual income they create should help propel you through your golden years.
Based on my initial experience of passive income, I feel real that real estate is best vehicle to build long-term investment. I live in Los Angeles and was able to cash flow my first rental property. What are you thoughts about starting out to build a passive income portfolio? I have utilized Lendingclub, online savings, and a small dividend/bond portfolio.
Viral marketing or viral advertising is a business strategy that uses existing social networks to promote a product. Its name refers to how consumers spread information about a product with other people in their social networks, much in the same way that a virus spreads from one person to another.[1] It can be delivered by word of mouth or enhanced by the network effects of the Internet and mobile networks.[2]