Unlike the express entry, IELTS is only required if you wish to claim points for language abilities. As for credential assessments, nothing was mentioned for self-employed streamHmmm...we are in the self-employed stream and IELTS was required for both my husband and me as were credential assessments. We used ICAS. My understanding is that all applicants must demonstrate language proficiency no matter the stream. I imagine an education credential assessment is optional and only if you want the points.
https://www.canada.ca/en/immigration-refugees-citizenship/services/immigrate-canada/self-employed/eligibility/selection-factors.html
At which stage did they request you for the IELTS & ICAS?