If no one else can help you,

I had the same problem some time ago and only got the "cryptonote-sumokoin-pool" working for solo mining, intranet only for security due noob in that area.
Sumo has some differences, so yes I expect changes to the config.example.json are necessary.
Compare it to the sumokoin pool source and you get an impression what is missing/needs to be changed additionally to the config.json.
But as I said, I used the easier way of my own pool and it only needed reading and time for trials.
I could test if it is still functional, have the whole server with the pool stored, possibly find some of my own documentation how to set it up.