A: Technically, yes. By editing the map_teams.txt file, you can assign the Bernabéu to any team (e.g., Atletico Madrid or a custom team), though it would be historically inaccurate.
They were frozen.
If you are playing an online crack (e.g., Red-Alliance), Stadium mods are visual only . The opponent will see the generic stadium on their screen unless they have the same files. PES 2017 NEW SANTIAGO BERNABEU STADIUM UPDATE
Upon loading into the stadium for the first time in Exhibition Mode, the visual upgrade is immediate. The distinct "skin" of the stadium wraps around the structure realistically. The digital ribbons that circle the interior of the bowl are crisp, displaying Real Madrid iconography in 4K resolution (for those running on PC). Most impressively, the mod captures the steep banking of the stands, creating that distinct "cauldron" effect that makes the Bernabéu so intimidating. A: Technically, yes