2) Have they signed up to The Science Based Targets initiative (SBTi)? And/or CDP?
Signing up to SBTi and publishing a target provides an indication that a company is following a clearly defined - and public - path to reduce emissions.
Choosing to disclose carbon emissions to the Climate Disclosure Project (CDP) is voluntary and provides a strong indication of whether standards and policies are in place as a genuine marker of intent. CDP data constitutes a large global dataset and can be used by researchers and analysts to track progress towards net zero and other environmental objectives such as plastic reduction and water conservation.
Both are useful indicators of how serious a company is about hitting their stated sustainability targets.