Drywall over Ceiling tiles and Plaster Ceiling
The only concerns are:


That the furring strips are on suitable centers (24" or less)
That they're anchored well enough to support the weight of the drywall in addition to the tile. 


Otherwise it should work just fine. You can take this opportunity to shim out any dips or humps, too. 

If you're going to the trouble of removing the tile, you might as well just remove the strips, too.