Yes, the Defender XL includes a set of compatible screws for the Springfield Echelon. Use Pin Set #2 included with your pistol in order to mount the optic.
The Vortex Defender-XL features 10 daytime, and 2 night vision brightness settings.
No, the Vortex Defender-XL uses the Leupold Deltapoint Pro footprint. The Vortex Defender CCW uses the RMSc footprint and can be found by using the link below:
https://www.opticsplanet.com/vortex-defender-ccw-1x-moa-red-dot-sight.html
With the correct adapter, yes!
This will not fit an RMR-cut, unless an adapter is used. the XL employs the DPP footprint, otherwise.
This can absolutely be mounted to a rifle!
Window size of the Defender-XL is 25.5mm wide, by 23.3mm tall!
With the correct adapter plate, or, if your pistol is cut for the Romeo-1 Pro, yes!
This will indeed with either a picatinny or Delta-Point Pro Mount!
With an adapter plate, this could be mounted to the RMR-cut. Otherwise, the Defender-XL wears a DPP cut.