To help kick start our project, are there any Pearl Gecko Altium or Eagle files that I could get access to?
As far as I know Silabs provide some format of symbols (not eagle and altium) for EFM32 device in application note AN0002, but it looks like the EFM32PG is not in this document yet.
We do not have symbols for any of the newer EFM32 or EFR32 devices... yet.
This is actively being worked on (I've been checking deliverables from someone we've engaged to do the work), but we're just getting started.
So, no ETA. You'll have to do the symbol entry on your own for now, but stay tuned. They will be forthcoming... eventually.