I certainly didn’t say they were looking at former BE routes more generally, but that if rumour of ‘Air France’ doing regional from Southampton is true then Hop! is plausible based on what I know and have seen of their network.
As for turning up at SEN, I’m not an expert on regional France but can safely say no chance. If they touch London at all it would be short-term into LHR to slot-sit for Skyteam. I’m afraid for the foreseeable future any London-Rennes is dead. If anyone desperately needs to get there it’s a relatively short ride from Nantes which is fairly well served. And one of the few French destinations I’ve been to recently.