I have searched WikiTree without finding any of the persons involved. But I have some for you. At Marianne's baptism Jenet Wood the child's faster (fathers sister,) and John Wood the child's morbroder (mother's brother) were godfathers. And at Jenet's baptism Jfr. (Unmarried) Marie Wood the child's faster (father's sister) also was godfather.
Yes, I think you should start a new question about the baptism of slaves, I don't know; actually, this was my first time I found a slave being baptized in Denmark. I think Walther Wood has been very rich cf. all the servants in the 1787 census and owing a slave in Helsingør was not normal, so he probably would show his acquaintances, some came all the way from Copenhagen to see a black man.
Thanks for the WW