Take a piece of cardboard and trace the top of the stove where the reflector/bonnet rests.. make a duplicate or two of the pattern,
PM me for my address and mail one to me,, I'll compare it to my Art Garland reflector/bonnet.. if it fits, I have one you could borrow to recast a repacement bonnet..
I'd mail a second pattern to the stove rebuilders out east, see if they have a reflector/bonnet in their parts piles..
Too bad you didn't pm me, You could have come by for a trial fit of the bonnet. I'm about 30-40 minutes west of where you bought that stove, I'm south of Flint by about 18 miles.
Both the Garland and Favorite were Detroit stoves.. Maybe, just Maybe some of the castings were shared.. it's possible.. and would help you
find the missing reflector..
Please take lots of photos of the dissassebly and rebuild of the stove.. We LOVE photos!
From the photos, the 'nickel' looks like silver paint?? or is it just the photo? You DO know the 'secret solution' for cleaning dulled nickel, right?