I think the bear will show up perfectly as it is - subtle, as you say, but not overpowering. If you decide to add the blocks I would leave the bear where he is and add the blocks to the lower right corner. If you decide to leave out the blocks, I would move the bear to the right and up by a smidgeon, maybe two inches in each direction?
I think a third border using the bear-bow fabric would look wonderful, as long as it isn't really wide - perhaps the width of the strips in the chevrons?
This is a lovely lovely quilt, and any mum would be thrilled to receive it!
Alison