Re Queen Alexandra - that is certainly what the sketch is suggesting. The Illustrated London News had some time earlier published the photo of HM wearing her Regal circlet with Queen Victoria's small diamond crown inside and so it is possible that the artist simply recreated the same configuration. It is impossible for us to say categorically what she might have worn - unless, or until, her dress books become available. What a joy that would be- if possible. I guess we can all dream, even though we know it is unlikely.