Background: a large consultant company wants to better utilize their consultants time when they're between assignments. The plan is to have an internal concept managing internal projects, which aim to deliver value to the company (sale demos, internal products, etc.) and also give the consultants the opportunity to gain new skills (for example get experience working as a Scrum Master).
Using Scrum for these projects are getting mixed results, since staff leave the projects pretty much immediatly when they get a paying assignment which makes it impossible to get a somewhat consistent velocity.
These circumstances also increase the demand on the ease of which one can enter these projects, for example readability of code, documentation of decision making etc. One risk is that this could increase the waterfall-nature of these projects, which I very much would like to avoid
So how to manage these projects? Project methods to use? Pitfalls to avoid, and how? Any help would be greatly appreciated