I think it's cool that you're running a low-magic campaign. My next campaign will be low-magic. But I also think that it's unfair if you limit the PC's access to magic but then all the NPC enemies that they encounter have magic.
Having to create weird optional rules just so that the PC's can't use their fallen enemies magic weapons and items is a bit cheesey, IMO.
Don't get me wrong, there are plenty of great creative ideas here, but I think after the 10th encounter with magic tatoo wearing enemies I'd be a little frustrated as a PC.
Of course the BBEG's are going to have some items, but for standard encounters I would suggest using higher level NPC's with no magic items on them. For example, add a few levels of commoner or warrior to your enemies.
Or add more enemies to encounters. Or give them items with very few charges left, like wands with 10 charges, single use/day items, etc.
But if you need some plusses to BAB and damage, I'd suggest bumping statistics or adding class levels, not creating mystic magical bonuses that disappear when they die.