The whole point of a deload week is to, well, de-load, reduce the load, volume and overall strain on the body. Mixing it up is great on a deload week on one condition: that the intensity is low enough that very little, if any adaptation is required on that week.
Repping out with bodyweight is not a deload unless you are stopping way short of failure. Your measure of 40-70% is correct, and for good reason. If you rep out, even getting close to failure, your inducing enough stress to cause a NEW adaptive response. Now you've defeated the entire purpose of the deload.
You can do whatever, as Dub said, it's not written in stone what you do, it's HOW you do what you do that makes it a deload week. Keep it light, keep yourself fresh, go to bed early, eat well, and then carry on next week. Yes deload is boring, generally. Personally I do the same exercises, I just go down to 60%. It's a bit boring in the gym, but makes for a much more relaxing week.
If you don't like deloading though, consider cycling. Instead of building up to a max, then deloading, then building up again, you build up to a near max, about 90% or so, then back off about 4 weeks worth of practice, then build up to a new 90% of max, and carry on as such.