i've found out that
Ashlyn and Ascelin have a connection (share the same origin), but there's no connection between them and Hessel. Hazelinus is indeed a derivation of Hessel, but has nothing to do with Azelinus. i've found Asselin in the database of firstnames of the Meertens Instituut and this name is related to
Ashlyn and Ascelin (the site doesn't say that but the name Asselin is composed of
ask and
lin , like Ascelin and
Ashlyn. well, that was it.