Thanks for using the Editorial Calendar, but I've never tried to embed it in another page like that. The first issue you're going to run into is the class instantiation issue that you mentioned. That's tough to get around since the Editorial Calendar acts like a singleton.
If you do work around that issue by changing the calendar code then you're going to run into a layout problem. The calendar really wants to take up almost all of the entire page.
The bottom line here is that you'd have to do a lot of coding to make the Editorial Calendar show up in another page.
Good luck,
Zack