if I buy this on wzm, will it carry over to wz/mw3?

The chainlink icon at the bottom indicates that the item is "connected" and can be used across MWIII, Warzone and Warzone Mobile.

Tap the “i”

The only items that are exclusive to WZM are the ones that have rarity associated with them. Items with chainlink can be used across all supported games, while items with the monitor icon are exclusive to PC + console.

Yes

yo guys if i put this skin on my wishlist can I buy it when its gone?

In blackops warzone but not mp

Crutch skin

yes purchases made using CoD points go towards your CoD account, purchases made with real money are platform exclusive which is why CoD point amounts, pro packs, blackcell, etc aren't cross platform.