Hi Sandy,
Usually, when a property is for sale, part of the buyer's agreement includes current residents' leases being honored as is, until they renew. Waiting lists are usually handled similarly. Since the Owner would know, and he has told you to operate as you would normally, then whoever is purchasing the property is probably honoring your Wait List. If the sale and takeover occurs on April 1, will you be able to house anyone before then, or will all these people remain? If there is no chance they will be housed, and you are not a Section 8 property (and I assume :-) you are not) then I would not continue to add to the Wait List. But that is just my opinion based on your Owner telling you to operate as you always have.