Found an earlier marriage record of Martin Donato to Mariana (Castillon), aka Marianne Duchesne. This puts a little more truth into the Castillon connection. Also this would make sense to why Alexander is listed as Alexander Castillon.

Castillon, Mariana, quart. lib. (Mr. Castillon Comexciante of NO & Naneta, neg. lib.) m. 21 Apr. 1800 Martin Donato, quart. lib. Legitimated 11 children. (Opel. Ch. : Reg. of B.; v. 1 p. 103)