Re: swimwear
A whole lot of athletic swim wear that cover the whole legs but I wouldn't wear that to a party.
Seems like a long sarong, swim wraps or a coverups that are available wherever fashion swim suits are sold.
I even saw really thin lawn kurti for wearing on top of the swim suit.
I think TLK was kidding about the gharara but there also gharara type colorful cotton skirts that swim shops sell to wear on the bottom.