If you feel this is a worthwhile business opportunity, then by all means go for it. My only concern would be this:
It can be more or less mitigated, but can it be fully mitigated? By letting people rent bikes from the top, you are enabling them to do something that they wouldn't otherwise have been able to do themselves (if you could climb to the top on a bike, I would assume you would have enough experience to manage the descent), so is there liability attached to the operator? Judging by current case law - the maricar operators don't seem to be held responsible for what is perfectly forseeable illegal driving behaviour by their rentees. The tour operator who took Otto Warmbier on his ill-fated NK tour don't seem to have any liability attached to them - then it looks like you needn't worry, but personally I feel it would be quite reasonable to argue that someone who has never ridden down a mountain of that length (assuming you are talking of the 5th station 2,305m) to fully know the dangers they are exposing themselves to when giving their consent. Also, if you are dealing with tourists who come from countries where driving is on the right, that would be another factor to add in to the risk involved.
Is the descent dangerous??? I've never done it, but if you were in front of a jury of non-cyclists, my guess is they would go for dangerous due to the length. I was coming down a hill yesterday and there were danger warning signs for cyclists - probably for the school kids, but the descent is maybe less than 110m (I can climb there in 5 mins) for the school kids and there is only a short section 10-12%
If you want to mitigate risk as much as possible, II would look for two guides (one front and back), signs to show that you tried to limit the bikes' maximum speed as much as possible by increasing CdA (tyres wider than 105% of the rim) and increasing .crr (gatorskins run near the lowest safe pressure) etc. Also, possibly run disc brake bikes (not that I am saying they are safer, just there is a perception). Also, I would put in place a written procedure for what you would do if someone made it half the way down and decided they didn't want to do the rest.