Thanks all for this clear reply, @maglib - one follow up question for your expertise if you could spare a moment:
If a trustee is not a professional fiduciary, but was a personal representative of the deceased grantor (assume an immediate family member of the deceased grantor) and is acting as the trustee in an ongoing capacity, but there is no business owned or operated by the trust - can the trustee contribute their earnings as trustee into a solo 401k and still avoid paying SE tax?
