Bird feeders and station, nest boxes.

Hi folks, after a long time out of my house (due to water damage) I’m reestablishing all bird feeders etc. Trying to reuse the good ones, so I have a couple of pole type feeding stations with hooks for the feeders and a small cast iron bird Bath/water container for the birds. I want to get rid of the some patches of rust and re coat to protect, but am finding all sort of differing advice when researched online.  My thought was to scrub with mild detergent (eco washing up liquid) and rub down the rusty bits, then re coat. So wondering if anyone has any tips for non-toxic method of re coating the metal stands? Many thanks for any tips or ideas. The birds are waiting!!

Secondly I want to put up bird boxes and have some left over larch to make one or two with. I sadly had to remove some Ivy where Blackbirds used to nest, so ideally would like to provide a possible safe nest site for them, seeing as that option isn’t available for them. So would I be best putting it in the Beech hedge near where the Ivy was or on the high stone wall where Ivy used to grow? I’d be grateful for any tips.