BCV will book fairly quickly and availability will be pretty spotty once the seven month window opens for non-owners - you'll want to make sure any guests you bring commit within the next three months. After that, you may have to move to a different resort to change room size - likely SSR or VAKL or OKW. I'm assuming your trip is in April - you'll might be able to find something to switch to until January or February next year, but your choices will get slimmer and you may need to move resorts to complete the reservation - April not being a high demand time (unless you are right over the popular Spring Break/Easter weeks - I don't know when Easter is next year).
And, unless you don't care about wandering about in a bigger unit by yourself, get a commitment. Most of us have learned that what seems like a great idea to our friends when its still theoretical (except for the reservation we have in our hands) becomes just not possible when its time to book airfare or get park tickets - and we can get left holding the bag (I'll tell you that four people in a Grand Villa was very comfortable - and since our intended guest had passed away, we really couldn't blame him and his girlfriend for canceling).