Hi, DAndersonRascher. Since your question is actually about Premiere Elements rather than PSE, it would be better to post it in the Premiere Elements forum. I'll move this over there for you.
The program may be a bit too complicated for 5th graders. Atlhough the program does include Videomerge, a simplified effect for creating greenscreen effects.
But have a look at my free 8 part Basic Training tutorial and see what you think.
Download the 30 day trial and find out in your classroom with your students
Start with The Help-and-Tutorials page http://forums.adobe.com/thread/1275830
Also the Premiere Elements FAQ List http://forums.adobe.com/community/premiere_elements/premiere_elements_faq?view=all
Several staff members have stated that this software is too complex for students of this age
What software did those staff members suggest as simpler alternatives?
Insanity is hereditary, you get it from your children.
Just my opinion....
If the teacher knows the Premiere Elements program, he or she can communicate the green screening techniques basic steps to these 5th graders. Much of the work is done in the preparation of the green screen photography and/or videography before it gets to Premiere Elements. And, I would envision the student working from instructions and not left to do troubleshooting and figure out the how tos.
When I see 3 years olds navigating iPhones and iPods and computers, I think that these older 5th graders will take to the program if they are guided to success. Success begets interest and creativity at all ages.
But, I would advise a tryout with a few students (Group A) and the free 30 day tryout from Adobe of its Photoshop Elements 11 and Premiere Elements 11. On the other front, I would have Group B working with Windows Movie Maker which I understand has a way to do green screen keying with something called "Rehan FX Chromo Key Green A4". I do not believe that the Windows Live Movie Maker offers this feature. But, I would have to do a lot more homework on this angle. You might want to explore
A friend and I frequently "discuss" what is easiest for video editing for the newcomer, Windows Live Movie Maker or Premiere Elements.
I would definitely not encourage the use of VideoMerge in Premiere Elements. When it first was introduced, it was marketed as an automatic version of ChromaKey. No substitute for ChromaKey as far as I am concerned. ChromaKey can also be used in place of the Green Screen Key or the Blue Screen Key. And, there is also a Difference Matte Key that can be brought into action if necessary.
Right now I have only Windows Live Movie Maker 2011 installed on Windows 7 64 bit. I just may look into the green screen effects of the Windows Movie Maker, unless someone who has posted earlier in this thread has been there and done that.
We will be watching for your progress.