So I live in Israel where we speak Hebrew and write RTL.
I'm new in WPMU Dev but I'm two years experienced with PHP and WordPress and I'm here to tell you - that is no RTL support.
I opened the access for you to see how it look from here - nowhere near the standard of pwmu dev.
I'd love to help and give consultion in this topic since I am an RTL user and I quite live it.
BTW I didn't check your themes yet, but for you to know that the rtl market is huge and one of the reasons for Avada theme's success is that it was one of the first that truly addressed the RTL market.