Presumably the stabbed lute refers to the murder of David Rizzio, Mary's secretary, who was originally a musician and who is usually portrayed as a lutenist although in fact he was murdered because of his secretarial role and his closeness to the Queen. His murder in front of Mary by Darnley and his supporters, appeared to be a turning point in their relationship after which she decided to get rid of him and her left hand in the red glove - the sinister hand - may refer to her (alleged) complicity in Darnley's murder. Ruthven, who lead the group of Rizzio's murderers, was in armour during the murder and the armoured man may refer to him, although it might also refer to Bothwell.
The white side of the skirt with the fleurs de lys may refer to her more innocent days in France, the red skirt - linked to the lion and surrounded by prickly thickets of roses and thorns - may refer to the greater dangers and bloodshed of her time in Scotland and England. The fact she is directing the lion of scotland into the path of the thorns of England's roses is presumably also part of this symbolic senario.
