Yes, it's possible to cut down most rigs in this manner. (If you want it to work, it does require redesigning the sails, and you ought to re-calculate all the rigging
loads- although it's unlikely that anything would be more highly stressed with a shorter rig, the shroud
angles will have changed and the distribution of force between the head
and main sails will be different.)
Yes, it'll greatly compromise the boat's performance.
Yes, it'll make the boat much harder to sell, and worth much less money when she does sell.
No, it's not a good idea. Two suggestions mentioned in previous posts- trade
her in for something smaller, or take the offshore route
instead- are far, far better options than trying to cut down the rig on an existing yacht.