In my experience, a lot depends on the couple's JW background and their extended families.
When my BIL and his newly Baptized™ bride were married, her non-JW father was allowed to walk her down the aisle and her non-JW sister was allowed to be her maid of honour. The Elders™ didn't want to alienate these non-JW people by making JWs look like intolerant fanatics. Plus, the bride had been Studying™ with the wife of one of the stuffed shirt Elders™, so some influence had clearly been peddled.
However, when Mr Scully and I got married several months prior, I was not permitted to have my raised-JW but unbaptized best friend be my maid of honour. Had I insisted, we would have had to find another officiant and somewhere else to have the wedding ceremony.