Is Cube Orange+ memory large enough to load all the features of Ardurover?

Cube Orange spec’s… 1MB Ram, 2MB Flash
Am I right in that the firmware resides in the Flash and that it is large enough to load the build with all the features? For example some are using two gps modules on their rover to obtain yaw and/or or heading due to issues with emi created by the spinning mower blade. And these feature of the software may not be included in the firmware flash if the memory is not large enough.

Am I good to use Cube Orange+ and I will get these features?

Yes. The Cube Orange/Orange+ or most any other supported H7-based autopilot should support all current features.