You can mix measures from multiple collection types for the MIPS Quality category. Benchmarks vary for each collection type. So, it is in your best interest to evaluate before you finalize the measures for submission to maximize your MIPS score and payment adjustment. 

The decision to pick the six measures must not be made without comparing and contrasting all available collection types (eCQMs, MIPS-CQMs, QCDR measures, and Claims), as the measures and collection types you pick can have a huge impact on your MIPS score.