Yes I would think the legs and feet are a concern, tendons & joints may well be damaged from sliding/colliding as well as concussion injuries, trauma laminitis and the obvious injuries.
Plus the effects of the stress, horses can and do colic after they've experienced high levels of stress so I would imagine that's a concern too. Rebalancing electrolytes etc.
But, they probably have a good chance if medical intervention can help, I wouldn't think that money will be a problem and don't they have their own dedicated equine vet team? People to monitor them and the skills on hand straight away.
The riders are in the best place, and the cyclist who was hit, and hopefully they will all make a full recovery from whatever injuries they have, and it might well be they don't want too many details released, their families may not have been contacted yet or they may just want some privacy, it's been a really high profile incident with news footage going viral so I wouldn't blame them.