Consult past managers, references

Discuss this option with your report first; then approach the exercise as a collaboration.

Absolutely include your report in the dialogue with past managers and maintain transparency.

You may get to the same answers just by asking your report about successful collaborations in their career and their favorite managers in the past. Identify one or two improvements you can make and note them in your notes to consider before each meeting with the report.

Contextualize past work experiences for what they are. If there are similar issues emerging in a current role, this does not mean that you will not have better outcomes. In fact, you are a new resource who may be more effective than previous bosses.