OK, so a day after I applied the paint stripper to the tub I scraped it off with a paint scraper, then pressure washed the tub to get it really clean.
I'm really enjoying the pressure washer. We don't use it constantly but it comes in really handy for things like this. It really cleaned off the last loose paint and rust.
I then spent about a week applying multiple layers of rust converter, waiting overnight for new rust to show up, and then applying more.
Today I sprayed the whole tub with white Rustoleum spray paint. This is not the final color for the tub, but this will be my primer layer. Again, I'm going to let this sit outside for a while, allow it to get rusty if rust is going to show up, then I will treat that rust and paint it again. It's kind of a process, but for a tub that will live outside it seems like it might be the best approach, especially because I do not want to be repainting this tub every six months. I still need to put another layer of paint on the tub, anyway, it was just too windy to make a good application.
The feet got enough layers of rust converter, and now I've put one layer of black spray paint on them. Same deal: they will live outside getting multiple layers of paint and rust converter as needed, until they appear to be pretty much sealed up.
I'm trying not to get impatient with this project, because getting impatient is what made the previous foray get all rusty and messed up.