Is it possible to strip the velvet from a set of antlers and if so, what does it add to the cost of a pedestal mount?

Don't know about the cost, but will very much depend on how hard the antler is underneath. I have had a couple of roe bucks where the velvet had died and was starting to peel off -. No reason IMHO why this couldn't, be peeled / boiled off and a reasonable antler remaining, but will probably need staining. But I did shoot a Red stag in early August and the antlers were still very much in velvet and growing - you could feel they were still very soft underneath. I am not sure would make a good trophy.

I have seen pictures of heads mounted with antlers still in velvet. Also perrouque heads on Roe are often mounted and here the antler never goes hard so hey must somehow beg able to do it.

Leave the velvet. I am jealous; I want a mule deer in the velvet very badly.

Yes, it can for sure be removed and then you will need to darken the horns or leave them white.

In my opinion, the natural velvet when left on invariably looks like Hell after a few years. Some might consider this blasphemy, but the artificial velvet used by some taxidermists looks better and lasts in a way that the real deal does not.