For me, among those tasks above, the killer is this weekend stay involving a Saturday and one other night. I am just not going to do that, or even go out of my way to do it. I don't think I ever did it, because I only had that task once before and I believe that there is only a certain level of inconvenience you should go to in order to complete these promotions. When I first participated in Accelerate (Into the Nights or something it was called back then) my target was something like 127,000 points, with reasonable goals. It was actually worth a bit of inconvenience, but nowadays the inconvenience is just not worth the reward (don't forget all the devaluations).
If I might make a suggestion, I believe IHG going forward should think about doing much more simplified versions of these promotions, along the lines of the current Hilton one: you get 2,000 points for each booking, and an extra 10,000 after each 5th stay. That is uncomplicated and drives bookings and business without the need to jump through all these silly circus hoops. I can't believe that these IHG promos really drive a lot of bookings any more. Most ordinary people can't be bothered with all the faff involved.