Looking for some advice on timelines please, for the best way to do things...
My husband was granted ILR (spousal route) in March 2019. We have started the citizenship application but not submitted yet.
We are due to visit Chicago in September. I’m going with work and he is accompanying me, I’m a British citizen so will be doing the visa waiver. Husband is South African, with the intent of losing his South African citizenship when he becomes a British Citizen.
I’m a bit worried we may end up in a situation where he is passport-less depending on how the timings go?
I initially thought that if we applied for citizenship, if we hadn’t had news by August then we would just do the US visa application process for him as a South African and get that in his South African passport.
Would this be viable?
My understanding with the new system is, like the ILR application, we won’t ever be without his documents for the citizenship application - he just takes them to the processing centre?
Any advice gratefully received

Would we be better waiting to do the citizenship until after we have returned? Will there be a limbo period whilst waiting for a British passport that we can’t travel using his South African one?