...and replace bow rails and deck hardware with 316 stainless...and replace
plastic through-hulls with bronze...

Were marelon through hulls around 25 years ago?

.and rewire with tinned copper
wiring..

"The only reason your boat hasn't fallen apart is that it is in fresh water"

Do the wires hold a boat together in FLA?
Would you replace circuits that had not failed in 25 years simply because they
might in the future?

.and restitch with doubled up Gore-tex stitching...

"The only reason your boat hasn't fallen apart is that it has been in fresh
water"

Few 25 year old boats have the original cushions and upholstery. You are
absolutely right, you can (and will) restitch with anything you like.

..and replace
rotted bulkhead walls with Starboard or Marine ply...

"The only reason your boat hasn't fallen apart is that it has been in fresh
water."

Rotted bulkheads (walls) are not endemic on older Bayliners. I wouldn't say
they are unheard of, but you will find them spread throughout a wide spectrum
of boats at this age. Usually caused by fresh water.
Guess the OP is just doubly lucky.