First, II exchanges are not the same as guests of the DVC member. They specifically don't get the benefits. As for the member having to be present to get the other benefits, I'm not sure I agree. The only benefits that specifically is stated that the member must be present is the cash disount and the UMP discount. Renters are also technically excluded from the pool hopping, discounts, etc. The reality is that any guest or renter is going to have the ID card that says member and will never be questioned. They've even given the UMP discount to guests when the member was not along even though the guidebook specifically says not only must the member be present but only the ones staying in the unit with the member is entitled to the discount.
For II requests, I'd Fax your info about a week before arrival and give any reasoning for certain requests. Don't get greedy as you will be low man on the totem pole, as you should be. If there's a medical reason, they will make every effort to accomodate it. They will not and should not give you a request above a member or the guest of a member except for true medical reasons. The fax number for OKW is 407-827-7710 and the phone is 407-827-7700. I'd call and find out who the room controller is then fax a very personal and nicely worded request.
I'm curious as to what you traded to get in. Even though Sept and Jan are the most widely available times for exchanges, few people still get in.