With the six non-special attributes being Strength, Quickness, Body, Charisma, Intelligence, and Willpower, and two of the three special attributes relating to magic and the third being derived, this is arguably a six attribute system.
The definition of solicitous is  someone who shows concern, care or eagerness. An example of someone who would be described as solicitous is a hovering and nervous parent.
A solute is a substance in which is dissolved in another substance, the solvent. A common example used to explain this is using salt water; salt dissolved in water. In that case, salt is the solute and water is the solvent. Its really that simple. Solutes and solvents can exist in more than just solid-liquid (aqueous) solutions, as solutions can technically be in numerous phases.