Those mortars look cool, but I wonder if players would struggle to tell where the mortar shell landed. For instance UCAP: The Sandpit runs mortars that fire smoke grenades a similar distance, however players and marshalls can clearly see where they landed.
As far as the grenades/mines go I like the idea. The issue with impact grenades is they roll after detonating so it ends up being debatable if you were under cover if you didn't see it land. Being hit by "shrapnel" would be preferable but the only option on the market is those pea grenades which are terrible, you may as well throw a handful of BBs through a doorway. The main issue would be FPS, but as far as I am aware a 200 FPS gun can happily launch BBs out 20 metres or so.