Fulton is much older when Gyro is still a kid (see this picture in the same frame story ->
https://i.imgur.com/n0RrT8F.jpeg and compare it with the one we are discussing, when Gyro is already an adult and his "father" looks younger" ->
https://i.imgur.com/311uAI7.jpeg)
Regarding the picture with all the relatives, in the panel right before, Gyro says "E infine io, oltre a una nutrita schiera di cugini di primo, secondo e terzo grado. A volte mi mancano così tanto..." and then, in the panel showing the picture "... e mi dispiace che il lavoro non mi dia mai il tempo per andarli a trovare."
This scene takes place at page 11 of the volume, and it seems to suggest that those in the pictures are the cousins he has just referred to.