<Legally, it can't be said that a person or group is acting as an agent of an Enemy of the nation (remembering always the significance of that capital "E") unless the answer to the question of Enemy contact is an unqualified and incontrovertible "Yes". "In effect" has nothing to do with it. Treason lives in the legal universe.

I take it you've never studied guerilla warfare. Through much of military history, guerillas have operated on their own with the goal of disrupting enemy operations. During the 20th century, common tactics included sabotaging railroad lines, power lines, and communications. They did this to hamper their enemy's ability to move and produce materials and to operate.

For example, during WWII following the fall of several countries, small groups of people gathered together to oppose the occupying power. Even before they had any contact with outside countries like Britian or America, they were considered enemy combatants. When captured, they were summarily executed in most cases.

If a group of individuals were to actively try "throwing a spanner in the works", that would be sabotage. It's extremely unlikely they would be prosecuted for treason, but they effectively would be acting to aid the enemy. As for the other questions, they would largely be irrelevant if the individual has gone on record saying he intends to hamper military operations.

Will anyone be charged with treason? I'd give 99:1 odds against it. Still, sabotage is "giving aid and comfort to the enemy."