WL Praxis vs ACTFL OPI and WPT

The Delaware Professional Standards Board has recently proposed allowing teachers to successfully pass either the Praxis OR the ACTFL OPI and WPT as one of the requirements for certification as a K-12 world language teacher. The Delaware State Board of Education has posed several questions as to why the State should allow a choice between the two assessments:
(1) Would offering an option lower the rigor for certification?
(2) Is there a comparison study between the WL Praxis assessments and the ACTFL OPI/WPT? Does the study show parity? Is one assessment more more rigorous than the other?
(3) Almost all content areas in Delaware, require a Praxis. Is the Praxis the best assessment for language educators?
(4) Some educators have indicated that the Praxis may be culturally biased. Is this true? If so, are their studies to prove this?

If you have any information that can help me craft responses to our State Board, I would be eternally grateful.