1. The batting cage idea is very risky. I’ve seen many of them close over the years and it is not anything close to passive income if you want to keep the business going. You have to continually promote it and target youth leagues, coaches, schools etc to catch all of the new players who grow up and want to play. I’ve played at probably 8 batting cages over the years and 7 of them closed.
Ask yourself how many hours a week do you spend sitting in silence, coming up with an idea and working on your idea? We’re so busy with our jobs that our childhood creativity sadly vanishes at some point in our lives. There are food bloggers who clear over $15,000 a month. There are lifestyle bloggers who make over $10,000 a month while living in Thailand. And there are even personal finance bloggers who’ve sold their sites for multi-millions.

Residual income is really the best Way of Life. It's a steady, reliable stream of income not directly dependent on the hours you work. Successful investors enjoy such freedom. Successful book authors get paid even when they don't write. The checks just keep coming uninterrupted, even when you relax. This is much better than hourly work. Much better that salaried work. 
I have a total of three CDs left. There is no way in hell I’m selling them after holding them for 4+ years so far to take the penalty. The CDs are for 7 years. That would be completely counterproductive. As a result, I feel very stuck with ever getting my CD money back if I wanted to. If the CDs were for just 1 or 2 years, I agree, it doesn’t matter as much. But combine a 7 year term with 4%+ interest is too painful to give up.
Residual income is the amount of net income generated in excess of the minimum rate of return. Residual income concepts have been used in a number of contexts, including as a measurement of internal corporate performance whereby a company's management team evaluates the return generated relative to the company's minimum required return. Alternatively, in personal finance, residual income is the level of income that an individual has after the deduction of all personal debts and expenses have been paid.