Aeltje Claes was a twin.

Baptism

1642 Jan 01; Claes Gerbrant; Aeltie; Elsje Rous
1642 Jan 01; ; Clara; Mr. Harmen [van Hoboken or Hobooken, Hoboocken, etc.]

Identification of baptismal sponsors

Herman van Hoboken was a school master.

Elsje Rous must be Elsje Hendricks Rous, who witnessed the baptism of Robbert, son of Thomas Sanders, "the mad smith":
1641 Nov 10; Thomas Sanders; Robbert; Jan Evertszen Bout, Cozyn Gerrits (wheelwright), Jan Verben, Lysbeth Dircks, Elsje Hendricks Rous

Is Elsje Rous a member of the family of Jan Roos, a relative of Emanuel gerrt de Rous van Angola, the wife of Jillis (or Gillis) Pieterszen, or Lysbeth Hendricks, "wid Laurens Janszen Deenmarcken" in 1659? Or somebody else entirely?

Marriage in New Amsterdam

1660 17 Apr; Michiel Verie; Aeltje Claes

Marriage in Wiltwyck

1664
11 May HENDRICK ARENTSEN, j. m., of Almelo, in Overyssel, and AELTJE CLAES, of [New] Amsterdam, in Nieunederlant [New Netherland], widow of Macciel Ferre, both resid. here [in Wiltwyck, now Kingston]. First publication of Banns, 27 April; second, 4 May; third, 11 May.

Source: Hoes, Kingston Marriages, page 501.

Published genealogy

"The Colonial Ancestry of the Family of John Greene Briggs, Son of Job Briggs, and Patience Greene, and Isabell Gibbs De Groff, Daughter of William Stoutenburgh De Groff, and Susan Hopkins" by Harry Tallmadge Briggs and John Greene Briggs, 1940, pages 243-244 and pages 329-330.

GEDCOM Note

Life Sketch ===
Partial research on Aeltje (Claes) Arents was published in an ebook about Hendrick Hendricksen Obe, who married another Aeltje Claes. [Marie-Pierre Lessard, Hendrick Hendricksen Obe, the Drummer: A Biography with Critical Notes on the Dally, Hoppe, Kip, and Grevenraet Genealogies; Also Discussing Hendrick Hendricksen van Eerlant and Aeltje Claes of Kingston, New York (Denmark: Marie-Pierre Lessard, 2020)].