Can s90 seats be fitted to S60

[IMAY2023]

Which PINs are you asking about? 
On the controller itself or on the Seat harness to Car's body connector? 

If you are asking about the Seat to Car harness connector.
Driver side connector:  94/505 
Passenger Side connector: 94/506
94/505:16 and 94/506:15>  15/50 CENTRAL JUNCTION BOX connector A30 (fuse number 40, 5amp)
94/506:11 From 7/255 SEAT BELT REMINDER MAT (power) > 4/176 SUPPLEMENTARY RESTRAINT SYSTEM SRS on F6.  (passenger side only) 
94/506:31 From 4/240 OCCUPANT WEIGHT SENSOR OWS  (LIN) > 4/176 SUPPLEMENTARY RESTRAINT SYSTEM SRS on F92.   (passenger side only) 

It looks like your new seats have occupant sensor and seat belt reminder but your old seats do not have. You can ignore them and just do not enable those from Orbit.  
But it just does not make sense. you are missing the main PINs, (CAN BUS, Power, Ground and some other stuff) even from the new seat's connector. 
Have a look the diagram. https://forums.spaycetech.com/attachment.php?aid=334 and search for  94/505:XX  94/506:XX  where XX is the PIN number on the connector.

[Helpful]

While I'm waiting for that mountain of spare parts that still need to be installed on my new seats (to make everything simple), I found another question. And these are the rear headrests. Now in my car the rear headrests fold with a physical button on the back of the seat. But in the new seat the headrests are already electric (the ones that fold with a button in the system menu). Perhaps this has already been discussed on the forum, if so, please give a link. Or how to solve this issue to integrate a new seat with an electric headrest?

[IMAY2023]

On the rear seats, you should have connector. PIN 5 is the ground and the PIN2 is the folding headrests. 
PIN2 on the LEFT goes to the CEM PIN FL75
PIN2 on the RIGHT goes to the CEM PIN FL76 
Then, you will need to set the 187  HEADRESTS 2nd ROW, FOLDING to 02. Which will give you the virtual button on the car functions page.