Something else happens in 1899...
Would not be opposed for further Indy integration beyond Jock Lindsey. Even if Indy isn't an implicit member, his grandfather certainly could be represented on the right.
The guy on the right is Charlton J. Taboret. At DisneySea, his signature is on the portraits, so, he's the painter of the group.
If he had a daughter who married a Jones... then his grandson could have been born that year.