I've attached a workflow that I think might help solve your problem. The steps I took are:
1. Select Records Tool: Select only the row that contains whether or now the column is required - in my example row 4.
2. Transpose to field name and required info
3. Dynamic Rename to add the required row as the description in the metadata
4. Dynamic Select with a formula to only choose the columns designated as "required" in the description
Let me know if this helps or if I have misunderstood your problem.