Speaking for the A220:
My outfit uses per default a reduced landing flap setting.
Full flap is recommended for contaminated and short fields (short field is not defined through policy and decision is up to the crew). Full flap is mandatory per manufacturer for approaches steeper than 3.5° angle.
A/T use is generally recommended but prohibited for steep approach. 5 kt speed increment are required by manufacturer if the A/T is used for landing. As this has quite an impact when operating on short runways, you might end up flying man thrust with Vref in limiting conditions.
We apply "operational landing distance" for in-flight calculations.