If there is a swap during the wedding then I hope it's a groom swap rather than bride because I won't be able to stomach Shivaay thinking Anika planned this and Tia was right about her and that she's a gold digger and obsessed with him.
Well Gul has already denied any scope of bride swap so that option is out...
As for groom swap, i don't think that is on cards either. I think it will be a marriage based on mutual consent, both parties may be hesitant or unwilling. But still the marriage will happen with both Shivaay and Annika's consent. With the right circumstances, this is possible. :)
So don't worry, don't think there will be any swaps...