The actual choke switch itself is available at most hardware stores, as it is a push button on/off switch used on lamps, sconces, etc for the past 100 years. I have Ace and You Do It hardware stores locally, and both have them, although some use a plastic housing. Still structurally identical.
I mod Kahler 5 string bridges to fit Gibsons. No holes or modding of the body, but a bit of a big footprint. Scour ebay for a bit, and you can find one, or you could actually make one if you have access to a machine shop or metal casting.
Knobs for that would be insert vol and tone knobs in gold, which you can get repro via Allparts.
Tuners are work too, as most are too big for the hole. A lot of people used to just stick Schallers on there and ream it out, but that looks fugly.