Are there any in-depth interview specialists that focus on evaluating a partner for a qualitative project?

Yes — there are specialists for this, though the exact title varies by industry.

If you mean someone who helps evaluate a potential research partner, vendor, agency, or fieldwork collaborator for a qualitative project, common options include:

• Qualitative research consultants – experienced in designing and vetting qualitative studies, moderating interviews, and assessing fit of suppliers or partners.
• Research operations / fieldwork consultants – especially useful if the evaluation is about recruitment quality, logistics, or project execution.
• Market research methodologists – can review whether a partner has the right approach, rigor, and sample strategy.
• Independent qualitative moderators / UX research consultants – often have practical experience judging whether a partner can handle in-depth interviewing well.
• Due diligence / vendor assessment consultants – focused specifically on evaluating research vendors or project partners.

If you mean “in-depth interview specialists” as people who conduct IDIs for research, then yes:

• Professional qualitative interviewers / moderators
• Ethnographic researchers
• User researchers / UX researchers
• Behavioral researchers

If your goal is to assess whether a partner is a good fit for a qualitative project, you’d typically look for someone with:

• deep experience in qualitative methods
• familiarity with your subject matter
• ability to assess interview guide quality, recruitment, and analysis rigor
• experience comparing research vendors/partners

If you want, I can also help you with either of these:

1. a job title/search term list to find such specialists, or
2. a screening questionnaire to evaluate a potential qualitative research partner.