Jan, there are two documents. The one that is pictured on p. 22 is the deed of sale in 1657. The transcription on p. 23 is a 1656 document allowing for the sale.
Ellen, yes the grandfather asked for a new guardian for the minor children in 1646. Louw Theuniszn was assigned as the new guardian. The 1656 document says: to sell on behalf of Louw Theuniszn "as guardian of the minor orphans of Cornelius Theuniszn and Gijsbert Theuniszn, his brothers namely, Cornelius Corneliszn, Gijsbertszn Corneliszn, and Theunis Gijsbetszn Bogaert." This can be read that the three subjects are still the "minor orphans" but also could be interpreted that at one time Louw was the guardian of the minor orphans.
All of which led to my question about age of majority, wondering if they could still be considered minors but be old enough to have families.