All of your options are good ones, so there appear to be no 'right or wrong' answers! Both size quilts are nice, but if your quilt is for a child to hug and drag around, the smaller size is probably best. The dark bubble fabric goes great with the rest of the fabrics, so whether or not you add another round or not, it would be great as binding and backing in MHO! Great colors too since they won't show dirt easily if on the floor a lot.

I like it "as is"

I think I spend more time "deciding" than actually "doing"

I love your choice of fabrics. I have some of that animal print in another colorway and you have given me ideas how to use it.

Yes, yes, leafy

I think you should add the other round. Not so much for size as the increase seems negligible to me but because that black bubble seems like the perfect finish of sequence for dark/light/dark/light/dark. Also as a child's comfort quilt I would be inclined to have a dark final round to better camouflage stains, dirt, etc from the dragging around part that always happens with well loved kids quilts. So YES the black bubble looks a perfect match to the rest. As far as backing, I'm a use whatever is available kind of gal for backings. I try to compliment but have been known to go totally scrappy or reversible on the backs. Go with what ever you like, either option sounds good.

I really like the bubble fabric; I think the quilt is more interesting and lively with it. I prefer the leaf for the back.

Ditto this and I love it!
peace

Yes. Add the black bubble print. And I would probably bind in the black, also.

If it is for a small child, stop. But I like a darker border on outside as a frame. You could bind with the bubble and that would take care of that.

I say that you should leave it as is if the child is under 5. Over 5 then go ahead and make bigger. I make baby quilts 40x40 and that's good till they are about 4ish. Depending on how fast they grow. Then I make bigger about 50x50 for kids who are over 5. That is what I have done for my two kids and their friends. It gives me an excuse to make a new one for them as they grow and tastes change. If you want the quilt larger, I would do the black both front and back. It looks great.