Do you have a 401(k) with work or an Individual Retirement Account (IRA)? Those can be good places for long term investments, before using an individual brokerage account, but it depends on your specific situation.
Otherwise, yes, a brokerage account with your preferred broker (TD Ameritrade, or whoever else) is a perfectly fine way to buy and hold long term investments like SPY.
I'm not familiar with any of these funds except UPRO. But I took a quick look, and it looks like several of them (including UPRO) are 3x leveraged funds. Doing passive long-term investing with leveraged funds is generally speaking a really bad idea. These types of fund are meant to be short-term trading vehicles, not long-term investment vehicles.
I'm not sure I understand the question, here. Do you need to worry about losing money? All of these funds can definitely lose a lot of money, if that's what you mean. That's true of any investment, but it's extremely true of leveraged funds like some of the ones you've listed.