I always suspected the one piece version of this figure and frog was Bagley. I bought one a while back which came with an Osprey bowl. The colours were a good match. Likewise I've seen green frosted examples which look very Bagley in terms of colour and finish. In contrast the two part version has a finer satin finish and does seem to match the Schweig Mueller pieces. Thus I thought this was one of those cases where the same shape was made by different makers.This is not unknown with Bagley (e.g. the wide Wyndham vase, the various bits which match Czech pieces, etc.). The plinth in the mirror set matching the Elf pattern so well also tends to support the Bagley attrubtion.
That said, without any firm evidence such as pattern books or ads, the above is all just speculation...