Car will not start after replacing serpentine belt

Does the battery have enough voltage to crank the starter over fast enough for the engine to start?

Does the check engine and security if equipped lights both come on for bulb check and then both go out, or does either or both stay on or flash?
Does the fuel pump run for two seconds once you first turn the key to run, before you turn the key to start?

Okay, if there are no lights on, the next thing to do is either check for a spark, or if you have some starting fluid, see if the engine will start and run for a few seconds after spraying a few small shows of starting fluid into the throttle body and then quickly making it to the ignition key and try to start the engine.
If it does start and run for a few seconds, than at least you know the ignition appears to be okay and if the fuel pump does run, the fuel injectors probably are not working and could be a blown fuel injector fuse, a blown PCM fuse, failed crankshaft position sensor or a security issue, but the check engine and/or security light should rule that out or not.
If it still does not start with the starting fluid, then start off with checking the ignition fuse/s.

Okay, I will as soon as you let me know the results of the few tests so I know in which direction to go.

Battery junction box fuse and circuit identification

Fuse Number Amperage Circuit
F1 . Not Used
F2 7.5 Generator
F3 20 Fog Lamp Relay
F4 . Not Used
F5 . Not Used
F6 3 Powertrain Control Module, (Bi-Fuel Control Module, 2000 Only)
F7 20 Horn Relay/Multifunction Switch
F8 . Not Used
F9 15 Fuel Pump Relay
F10 . Not Used
F11 20 PCM Power Relay/Ignition Transformer
F12 . Not Used
F13 20 Heated Oxygen Sensors
F14 7.5 ABS Control Module
F15 7.5 Headlamp (Right)
F16 7.5 Headlamp (Left)
F17 7.5 Headlamp (Right), Instrument Cluster
F18 7.5 Headlamp (Left)
F39 . Not Used
F40 (1999) 20 Ignition Switch/Light Switch, Central Junction Box Fuse F26
F40 (2000) 20 Light Switch
F41 (1999) 20 PCM Power Relay
F41 (2000) 20 Ignition Switch, Fuse F26
F42 40 Central Junction Box Fuse F37
F43 . Not Used
F44 . Not Used
F45 60 Ignition Relay
F46, F47, F48 . Not Used
F49 60 Engine Cooling Fan Relays
F50 . Not Used
F51 60 ABS Control Module
F52 60 Rear Window Defogger Relay, Courtesy Lamp Relay, Central Timer Module, Central Junction Box Fuses

That was included in them, that is the central junction box. These two.

I have no idea what that is. A search of that part number comes back with nothing at all.
Perhaps you should include the location of where you found it, what it looks like and any color wires going to it.
If you are just asking a general question as to what it is, where did you get this part number from?
A snap shot of it may also help identify what it is along with all the other information.

Yes, gas or kerosene in the oil pan will dilute the motor oil and prevent the motor oil from doing its job of lubricating the engine parts such as the crankshaft and camshaft bearings and without that protection the bearings may go without proper oil lubrication long enough that the bearing overheats and fails causing bearing damage and ruin the crankshaft or camshaft as well. Not to mention lose oil pressure because of the worn bearings creating even more damage from the even more lack of motor oil which would eventually cause even more parts that depend on motor oil for lubrication to fail.
Are you saying that is a serpentine belt tension-er that you are holding in your hand?
With all that done said and the fact that the belt flew off and the gas in the oil, I think you should better check to make sure that engine did not lockup because of the loss of oil pressure.