I’m pretty sure HJPEV could precommit to not using the stone himself, in order to use it on others.
I don’t think that would be enough. In canon, Quirrel wanted the stone to use on Voldemort, not on himself, and he couldn’t get it.The only way to get the stone in canon would be to want to have it to keep someone else from having it. HJPEV would want to use it on other people, therefore he can’t get it. Unless he could get an exception for wanting to give it to someone else, who would then be able to use it.
I don’t think that would be enough. In canon, Quirrel wanted the stone to use on Voldemort, not on himself, and he couldn’t get it.The only way to get the stone in canon would be to want to have it to keep someone else from having it. HJPEV would want to use it on other people, therefore he can’t get it. Unless he could get an exception for wanting to give it to someone else, who would then be able to use it.