I agree that the purple hoodie you posted with the lambs is definitely the same as the Polka Tots hoodie.
I see the checkered flowers on the hoodie as well so it is likely that the yellow romper and socks belong there. The polka dot collar is the clincher!
As for the romper with the apple, I think that must belong as well because it looks like the same apple and butterfly on the hoodie. And again the polka dots!
What about the building on the romper and the hoodie in the Polka Tots photo. A schoolhouse? A barn? The theme is lambs, flowers, apples butterflies. Maybe a farm? School? Mary had a little lamb?
It looks like all these items belong together. You are a great detective susandaily!