I found a 1900 census. It was dated as 1 June 1900. John and Catherine had only been married for a couple of months. I know this because I found a pic of the ledger that shows that John applied for a marriage licence on 16 April 1900. So they had to have been married between Apr. 16th and May 31st of that year. That is if the laws on obtaining a license before the ceremony applied then. Not sure how to look that up. Also in the 1900 census under "how long married" the answer is "0" for both of them. Either this reflects that they had been married under 1 year, or (mercy me) they were not married yet and were living under the same roof anyway. I assume they had a private (apartment) dwelling. I do not see anyone living in the same household.
There was also a birth month and year for Catherine and John. John's birth month and year matches the ss death index. Catherine, it turns out, was born in April 1871. That clears up a lot. whew!