Interesting fit... the girl fit looks perfect, the old guy looks like a bear riding a tricycle.

The problem with the neck is because you have all the weight at the front of the bike, if you get the handlebars upper you will shift weight to the back and obviously the pain will go away.... d u h !

I would use just to start lemond formula for saddle height, then put the saddle 5 cm behind the center of the BB, then lower the stem at the same level than the saddle. That will stretch the old man enough to look like a real rider, probably even the back will start hurting, in that case lower the handlebar 2 or 5 mm. done.

Saddle needs to be level just in case and forget KOPS, that doesnt work with everybody.

Good luck.