Further, I've found a genealogy for Ferdinand de WITT and Elisabeth WEEMA's daughter, Elisabeth :
There are lots of photo's here (Elisabeth was very pretty) - and I think also there are connections in this family to Sumatra etc (I don't speak dutch, but a little german - enough to get the gist of the dutch!)
http://www.kranenburgia.nl/I-J.aspIt says: Elisabeth de WITT, daughter born 1846 to Ferdinand de WITT and Elisabeth de WEEMA
married in 1869 Groningen to Ipojé KRANENBURG (b1831 Groningen-d1916). It was his 2nd marriage; his first wife Johanna and their two daughters died in 1864 during an Epidemic and only their son survived. Ipoje and Elisabeth went on to have children:
Ferdinand 1870
Albertus 1871 (d 1872)
Albertine 1872
Elisabeth (Betsie) 1875
Anna Clara 1876
Roelof 1880
Ipo 1881 (d 1881)
Aukie Marta 1882
Iopje died in 1916 and Elisabeth 3 years later in 1919.
Overall, this all seems a very likley genealogy line for Ferdinand and Archie, the WW1 lads!
But what is giving me pause is that you have : Ferdinand de Witt married a Petronella Weema (Wiema) in Groningen. And that one of their daughters married Dr. Diephuis, father of the Fen Diephuis.
Cheers
AMBLY