Ehhh... Much of what you said doesn't make much sense.

You need a level 34 Conjurer to have access to Stoneskin, and I think it was level 22 or 26 Marauder to get Mercy Stroke.

That said, if you're going to get a Bard at 50, you cannot Cross-class those skills for it. Bards can only X-class with Pugilist and Lancer, and you need to be level 30 Archer and level 15 Pugilist to have access to the Bard job.