I'm going to call it and say no
I don't think an old party will want to be in cahoots with a new one, particularly not if Nigel Farage stays at the helm. I don't think Nigel Farage wants to be prime minister - I think he will find a replacement before 2029.
Just my 2p worth
Meanwhile, is Starmer relying really heavily on advisers who are playing practical jokes on him? Harriet Harman?!
editing to add - I also don't think Reform will want a coalition with the Conservatives either. We're not in friendly "I agree with Nick" territory I don't think.
stranger things have happened I suppose. Everything is very strange now.