It's obviously impossible to prove a non-overlap (or overlap) between these groups from where we sit without more information, but I have a feeling that the people protesting the soldiers' prosecution do not want a ceasefire, even for selfish reasons.

Same people?

I really don't think these are the same group of people. From the article:

The strike was ignored in some areas, reflecting deep political divisions in Israel after nearly 11 months of fighting.

Those are the people you're thinking of, and they aren't striking.

Entirely different groups of people, and they're profoundly opposed to each other.

At the core of this massive protest/strike are groups which have been against the bombardment of Gaza from the outset, and protesting Israel's war against Palestinians for years.