Okay, let's see. Grizzle is ECL 10. He's 6 HD, so that's 6 ECLs right there. If you slap the winged template on, that's another +2 LA. Since it also has the abilities of a paladin mount, that's another additional +2 LA on top (DMG, p. 200, first column, under "Paladin Cohort Mounts"). That brings us to ECL 10. If you want to keep those two fighter levels, you're going to have to drop the winged template (since you can't drop anything else). Also his HD would be 6d8+2d10+Con bonus (he doesn't get d10s for his dog levels)-- you would treat Grizzle as a multiclass dog/fighter when calculating BAB, saves, skills and whatnot.
I'm not sure how you did his stats (or how he managed to have a natural armor of +12!

)... my suggestion would be to start with a riding dog's base stats, add bonuses from the winged template on top if you're keeping that (+4 Dex, +2 Wis), plus any from the paladin special mount (+2 Str, and an Int of 7), plus 1 ability score gain for being 4 or more HD. You would not use the 28 point buy method to buy his stats (since all nonhumanoid cohorts simply use the base creature stats in the MM).
I also have a few other questions, such as how did Grizzle wind up with Improved Trip if he didn't take it as a feat (I know he would have Trip as a special ability for being a wardog)? Also, what is the Natural Heavyweight feat and where is it found?
I suppose if you like, I will stat out your dog for you to save you the hassle, if you tell me what you want.