You can run the APU bleed instead of using ENG 1 bleed during the taxi but it puts more load on the APU and reduces the fuel saving. However, it’s still better than running two engines. I’m not rated on type any more but we had a list of conditions where SETO wasn’t approved.
As for opening the crossbleed - again it increases fuel flow on ENG 1 but may be preferable for comfort. Just be aware that on the NEOs (not sure about PW as my company only flies CFM) there is a large increase in idle thrust. For that reason, we were recommended to keep the crossbleed on AUTO (I.e. closed).
champ