Can someone please tell where can i find these creeps ?
Canons can be found just about any place you find creeps. Invasion, heist, campaigns.
Purrickily Pears can be found in invasion and upper level campaigns.
Ch. 21 stage 2 and 4
Ch. 22, stage 2 and 6
Ch. 23, stage 7
Ch. 25, stage 3
Ch. 27, stage 7
The Cannons start showing by Chapter 5, Stage 5.
It turns out that they actually vary by server. On server 1, they can first be found in ch. 2, stage 3. The stages I mentioned for the purrickly pears are also from server 1.