OK so I have a couple more names, and still a few of the original ones in the running. I think we are keeping Chunker. Here's a picture for inspiration:
Tukeva Kettu (means sturdy/chunky fox)
Into (zest, zeal)
Sonni (bull - I keep calling him a bull in a China shop)
Ensio (first)
Koru (jewel)
TOO MANY OPTIONS.