Who are four of these people?

I only know who one of the people in this photo is.

The young lady on the far right is Tena/Trientje Janssen Ufkes (1895-1986).

Tena was born in Bear Creek Township in February of 1895 and died in Carthage, Hancock County, Illinois, in 1986.

I do not know who the others are in the picture. This photograph was one that my grandparents had. Tena's son John H. Ufkes (1917-2003), was my grandfather.

Any suggestions as to who the others are would be greatly appreciated.