I'd sand it to bare metal and prime and paint it ... but if you have done research and found other solutions, trust your research.

I have never rented a spray gun ... but I have painted bikes with rattle-cans. I don't see how it is different than painting anything else.

As for taking it apart .... if yo have done it before you will learn a lot ... translated, there is a world of potential frustration to be had ... For Free!!

It is all really simple if you are at all handy--I am not, and I have done it a few times. Go online to park Tools and YouTube and watch a bunch of videos, be careful as you disassemble things so you can remember what order things went, take notes, put all your components and hardware in bags or boxes--labeled--so you don't have to hunt for some fastener which hasn't been made in six years.

There is no part of building or rebuilding a bike which is difficult, but you have to pay a little attention. The result is that you will have a feeling of deep satisfaction because you will have successfully made that bike your own--and you will only get better at bike mechanics, which is handy if you plan to ride a bike.

Also ... if anything goes Really wrong, you can wander down to the local bike shop, explain what happened, and get them to do it right. Unless you go after the thing with a hammer or hacksaw, you won't lose a thing.