Red
With Blue out of the way, the last obstacle is Red. In preparation, all eleven (or ten) Rare Candies will be used. They are all rather easy to find with a guide even without Flash. Though the one at the Light House is only accessed by entering the room from above by jumping down. Using the stairs up would require fighting trainers. In Crystal, the one in Teak City isn’t obtainable, as the place is guarded by three trainers. Combined with the lower amount of battles, Feraligator in Crystal is two levels weaker than the one in Silver.
Finally, Feraligator gets three-four of each vitamin and four-five HP UP. I honestly don’t know how those work and as long a I can beat Red, I don’t have to.
Pikachu seems like a threat with his speed and thunderbolt, but being unevolved its stats are just too low. A single Return takes it down.
Venusaur can take two Ice Punches (Blizzard may be better), but it wastes time charging Solar Beam or using Sunny Day. By swapping Pokemon, Feraligator can avoid a nasty Solar Beam.
Espeon gets one Psychic in before it falls in Silver with a second Surf. In Crystal, it outspeeds Feraligator. Hoping for a Crit or Reflect may work. In the latter case, the other Pokemon have to be switched in so Reflect wears off. Reflect shouldn’t be there when Snorlax is around.
Snorlax is the largest threat, as it takes some Returns, while retailing with a mean Bodyslam. It can also recover. The solution of this is Dynamic Punch, which puts it in range to be beaten by another Return. Confusing it makes it even better. It also wastes its first turn with Amnesie.
Blastoise is sturdy. Gambling with a Dynamic Punch to confuse it is possible, a weakened Feraligator may not beat it fast enough with Return.
Charizard survives one Surf and its one attack can beat a weakened or unlucky Feraligator, even more so if it is a crit.
Espeon, Snorlax and Blastoise can easily beat Feraligator, so some luck is required. Going for Dynamic Punch was the biggest surprise. In Crystal, Feraligator didn't even survived this battle. Out of all 12 participants in this battle, only one survived.
The challenge ends with a total of 117 battles and 284 faced Pokemon in Silver. Feraligator wasn’t able to reach level 74, being short of 20 exp. In Crystal, the challenge ended with a total of 109 battles and 267 faced Pokemon. Feraligator loses out on two levels, but may get to level 72, if it beats all six of Red's Pokemon.
Battle Count: 109
Current Level: 71-72
Spreadsheet with all Encounters and their number of Pokemon: Looks like I an't post google sheets...
Totodiles learning set, HM Distribution
Each of the four lines represent the place in the attack menu, so Scratch will be replaced by Cut, then Cut will be replaced by Return and so on.
Silver
1. Scratch 6. Cut 10. Return
2. Leer 5. Fury Cutter 7. Bite 13. Earthquake 14. Dynamic Punch
3. Rage 9. Ice Punch
4. Water Gun 8. Surf 11. Whirlpool 12. Surf (one Rare Candy requires Whirlpool, switch back to Surf afterwards)
Kenya the Spearow has Fly
Shuckie the Shuckle has Strength
Sandshrew has Cut
Dratini has Surf and Waterfall
Crystal
1. Scratch 5. Cut 9. Strength 10. Whirlpool 11. Return
2. Leer 6. Bite 12. Earthquake 13. Dynamic Punch
3. Rage 8. Ice Punch
4. Water Gun 7. Surf (Cut is needed in Kanto and for some Rare Candies, switch back to Surf afterwards)
Togetic has Fly
Shuckie the Shuckle has Strength
Dratini has Surf and Waterfall