94 SL1 wannabesubmarine in Key West has a couple problems

My 94 Saturn took sea water over the floorboards but not up to engine.
about 5 inches on rear carpet and 2 inches over front floor carpet.
cleaned out within an hour with multiple fresh water soaks and drains
(Hand dumping with a cup(thought I was on a sailboat with a leak))
Also rinsed engine compartment and undercarriage a few times.
Now the speedo doesn't work It did once after the first day but it is
out again now.
The odometer hasn't worked in a year I know about the gear just
haven't
fixed it.
The check engine light comes on after about 5 minutes of driving and
stays on after that.
The door open take out your keys chime stays on all the time the
ignition switch is turned off- checked door switch and it is good and
even cut the wire to the switch and shorted and opened them but the
chime still sounds. Can I just leave the 5 amp fuse to the chime out
forever? it seems to control the memory of the radio so I would like
to fix this and be able to leave the fuse in.
The auto seatbelts don't even try to fasten.

please let me hear any comments you may have on what to do to fix
these minor problems. I am going to keep it so if you tell me to sell
it give me an offer (;- )