I've opened a couple questions about the Jolla tablet on Together and it looks like some of the questions asked in this thread might be covered. So there is the list of the links to those questions (hope this won't trigger any built-in antispam protections :P) :

Will the OS be fully open source (mentioned on the page)?
Open bootloader?
What GPU will be used ?/
Wacom digitizer ?
Jola smartphone & tablet pairing (like on webOS)?
Notification LED ?
Will a flashable recovery image be available ?
LPM/glance screen ?
FM transmitter ?
NFC ?
Pressure sensor & thermometer ?
Magnetometer ?