What counts as a conflict of interest for an executor in Alberta?

This answer covers the law of Alberta.

A conflict of interest arises when the executor's own interest competes with their duty to act honestly, in good faith and in line with the will. Being both executor and beneficiary is not itself a statutory breach. The duty is to act with the care, diligence and skill of a person of ordinary prudence, and an executor named in the will is a trustee of property the will does not dispose of, so trust-law duties of loyalty apply.

Whether buying estate property or favouring themselves crosses the line depends on the facts, and a lawyer can confirm. If a representative refuses or fails to perform a duty, the Court may order them to perform it, impose conditions, remove them, or make another order. Removal is an option, not an automatic result. A personal representative with professional skill, such as a trust company or lawyer-executor, must apply that higher degree of skill when acting in that professional capacity.

Before going to court, Alberta's guidance is to try to resolve it by discussion first. A co-executor can also apply to remove another co-executor who is failing in their duties. The Public Trustee does not get involved in private disputes about how an estate is administered.