Get an independent inspection from a Licensed Marine Contractor.
Make sure they get in the water and check the seawall at low tide.
They should use a probing stick to see if they can reach the bottom of your seawall within one foot of the topsoil.
If they do, you may have an undermined seawall or you may need a footer.
They should check each of your piles for parasites and corrosion.
They should check your deck substructure, stringers, braces ect.
Contact The Dock Experts for your complimentary consultation.