Sorry for not replying faster but I was on a nice internet-less vacation. Just send the whole list, I can manage easily myself to find the missing dates. If you don't have the rikishi-ID I would like to have something to make an easy ID of the rikishi though (like last shikona plus birth date).
I hope you've enjoyed your vacations. I have sent to the e-mail adress given on the DB website a very short list with the date of the death of rikishi I've not seen on the DB. I can send you the rest but I think you have got most of what I have.