It is easy to rent points. They do need a renter though. A non owner cannot do anything with a point. Points rental is really you making a reservation on their behalf.
Concierge Collection is direct points only and a poor trade value. RCI is open to all, but is again generally a poor value based on the cost of DVC. DVC points are best used to book DVC resorts.
I have 3 contracts and can use the points easily together, but sometimes have to change the order during booking if I want more to go from one than another.
Renting points out is so simple with a broker! We’ve done it a couple of times and I haven’t had to wait more than a few days. They tend to have renters waiting to borrow points rather than the other way around at the moment.
I haven’t booked anything other than DVC resorts so I can’t help with that. I would probably just rent points and spend the money if I didn’t want a Disney trip.
December does seem a good fit, but if you’re buying direct you can generally get any use year (or resort) you want. That might be just what they’re pushing at the moment. Maybe it’s because it’s less desirable as you will only have 2019 points for the next 10 months but earlier use years will soon receive a second batch?