i know of the company called sabeel that provides female waitresses in lahore. I've attended 2 weddings that had them. Their number is 042- 5712601. They will provide you with the waitresses so you can arrange the wedding in any halls u want.
As for halls, i know that there's Qasr-e-noor( the one in garrison golf and country club) which is suitable for you. The hall has high ceieling. the partition is as high as the cieling.( and its not like tent running through making the hall look ugly) You can also have it removed later if you want. Make sure you have the same Qasr e noor. others arent as good..