Welcome to the forum
In regard to physical mounting hardware? I sure don’t get the sense that there are proper standards, perhaps there are some quasi-standards around. The Framework 13 and 16 use mounting brackets adhered to the screen which then gets screwed into place. See here, community.frame.work/t/unofficial-guide-to-aftermarket-lcd-replacement/15890. I don’t believe those brackets are available separately. But pull-to-release screen adhesive strips are available on ebay & anyplace else you can find laptop parts.
See Framework’s github. It looks like they have CAD files which should give the space available.
Intentional BIOS restrictions? Such as whitelists which some other manufactures use to lock you into only the parts they intend for the model to use. Yeah, Framework sure doesn’t do anything like that!
Of course using a different screen will make it up to you to get it working. Forgive me if you are already aware, but many internal laptop parts won’t be plug-and-play the way externally attached devices are. For screens, there are a few quasi-standard LCD display-side pinouts. OLEDs go a different way with pinouts. And they require different voltages. You’d need to find or build a driver board, and have a custom cable made. One community member had a cable made and found it wasn’t too expensive. Mainboard-side display connectors don’t seem to have any standard pinouts, so expect each manufacturer to be different. An ASUS cable won’t work. Framework’s pinouts are on their github.
You might want to follow this thread, community.frame.work/t/build-log-fw13-dual-asus-zenbook-duo-oled-panels-custom-chassis-custom-pcb-daily-driver/82046. They plan to tackle building an OLED display driver for a Framework. And iirc the Framework 13 and 16 use essentially the same mainboard-side display pinout.