the priest does not use the older long S form at all, that was actually mostly gone out of usage by this time. It is definitely a Z.
Albert on baptism of his first son has signature that is more legible, writes Canslay.
His first son is named Albert, his second son is named Jérémie, baptism for him in different parish and the name gets written Quinzelay, sigh. Albert didn't sign that one.
Next child is Paul, name written Camzelay, Albert signs Canslaes.
Next is son Verance Adonatger (no clue what that would be originally, obviously phonetic), family name written Kinsley, Albert not signing
Next is Anastasie Kinzeley, Albert signs Canslaeif
Next is François Xavier Camzelai, Albert signs Canslaef or Canslaes
Next is Marie Augustine Ruth Canslais, Albert signs Canslaef or Canslaes
Next is Jean Noël Kingseley, no signature
Next is Louis Kenselay, Albert signs Kingsley
Next is Marie Magdeleine Kenselley, Albert signs Kingsley
Last is Marie Théophile Kengselay, Albert signs Kingsley
Albert is listed as ''cultivateur'' or ''agriculteur'' (farmer) on records where it is mentioned.
As far as the name change, as you can see, he changes the spelling on his signature over time, it's the same handwriting so there is no doubt about it being him.
Libbeus or variants thereof is definitely not a French name, so might have been dubbed Albert and gone with it afterwards. Abjurations records that I can find stop at 1757 so don't know if he renounced protestant faith after arrival here.
That he names his second son Jérémie is further evidence that he is son of the parents of Libbeus. Just can't tell if he is in fact the same man as Libbeus, FS didn't have a link to the actual baptism for that one, just a file.