A week and half into the new solution I am fairly happy! The little pockets held knee pads securely enough that I didn't feel any bouncing even in jumping, no velcro needed.
I glued velcro hooks on the top of hip pads and the capri pants' waistband serves as loops already. Had to use stronger glue to make sure velcro stays on pads. It works for me, not moving but drags down the pants a bit - need pants in smaller size... Overall satisfactory though!