POSSE, POSSEE, MAYNARD, FULLAGER, FULLAGAR, WATSON, WALTER

I am researching the POSSE(E) family, but have many other surnames in and around Marden, Yalding, Headcorn, Woodchurch, Sutton Valence kind of area!
I have a hunch that we are related to the WALTER family (I have a POSSE-WALTER marriage) but can't find the parents of William POSSE born c 1784 in Boughton Monchelsea. He married Mary Watson in 1808 in Maidstone (All Saints). Almost all their male children have Walter as a middle name and it is a recurring theme in subsequent generations. Most families have at least one child with the middle name relating to a maiden name, so although it is a bit of a leap of logic, I feel it is worth pursuing!

Sarah Evans (nee Possee- the extra e seems to have been added in the early 1800s)