I don't see a way to wire an original screen with baseboard < 7 with this particular list. Probably the best would be a standalone GPS feeding the Trutrak AP. Then the EFIS would be:

Serial 0:AF-AHRS
Serial 1:SV-ADSB-472
Serial 2:SV-XPNDR-261
Serial 3:AF-ARINC
Serial 4:GPS-2020

A hardware upgrade would free up Serial 0 by changing to the SV-AHRS-200. You could save another by swapping the AF-ARINC for an SV-ARINC after upgrade. And save another with a Wi-Fi ADS-B receiver but that's going to far.