you're right, this is obviously only something for people privileged enough to have their own house, good credit etc.

well, if you have a "loan on renewables", you won't be paying money towards electricity production so you could use the money you saved to pay off your bank.

Neglectable in this case means that your long-term cost of conventional energy consumption is (very roughly) the same (give or take a few hundred over your lifetime, there are calulators online) as the cost of installing your own pv system.

if you want go to all the way and calculate the total economic value (think energy independency, avoided CO2 emissions, cleaner air, a future for your kids etc) producing your own power will be a lot cheaper.

According to Wikipedia, it's onshore wind. The large up front investments are true and the amortization period is longer than for fossil fuels but compared to the societal and long term/eternal costs of using fossil fuels and nuclear energy, the costs are neglectable

renewable energy is cheaper to produce so the free market will lead to lower costs for everyone unless the free market isn't actually free because companies are conspiring against consumers to siphon off their money. well, good luck