I haven't posted on your sitch before, and I have admittedly have been a lurker, but it is because I may very well find myself in your exact situation sometime in the not too distant future. Frankly I am amazed at how well you are handling everything, how strong you are through all of this, and that you are putting your concern for your kids first to make sure they are as comfortable as possible.
FWIW, I think your second option above is the best way to go. Taking over the generic stuff will ensure there are things already in place, but letting them pick out some specific items will include them in the process. I think it is the perfect approach.
I hope everything goes well with your son's Karate and also with telling him about what is going on with you and your H.
