Hi !
* How is the Stencyl community? Will I be able to forward my pupils questions if I don't know the answer (yet)?
I think the community is quite dynamic, so it won't be a problem
* How stable is Stencyl? Nothing will mess up my lesson more then bugs / crashes, etc.
It is quite stable. There were some time it wasn't stable but usually because of problems like changing Java.
The actual version is really stable I think ( for Windows at least).
* If you read the above situation, do you think this will be manageable?
yes .
* Is Stencyl a useful / realistic program if pupils will want to work in game development after their secondary school?
The advantage of Stencyl is that it uses real code. You can actually preview the code and see the code written. You can also just view the code for blocks. Which is really great for learning.
So even if it less known than some other constructions engines, I think it's better for this reason.
The other great thing is that it's cross platform, you can test on android in the free version for example
. This should be motivating for students.