The serious watchers will likely play their cards close to their chest and may not bid until nearly the end of the auction. A few bid sniping tools will probably be deployed in the final ten seconds. The two Barrons and the Raleigh are genuinely quite rare and not run of the mill
eBay fare. Dawes tandems aren't super-rare, but they were expensive bikes new and have their dedicated enthusiasts. None of these bikes will appeal to the everyday buyer, but it's not them that are watching/bidding.
The fumble-fingered riders who can't manage friction shifters will give the old vintage ones a miss and if they bid on anything, it will be one of the two moderns. None of them have unrealistic start prices, so they will almost certainly all sell at first listing. I'd be very surprised if any don't go.