TL;DR in bold.

Before we go to the Elite Four, I recommend that we get Blizzard on Helix (Fonz is also acceptable but he has lower Special. Air Jordan is not preferable because he naturally learns Ice Beam.)

"But /u/NameAlreadyTaken2, this is going to be unnecessarily complicated!"

Nope! TM14 Blizzard can be found inside the Pokemon Mansion! It is at Point A on this map. This is conveniently right next to Switch 7 on our currently-planned path.

Assuming we get Surf and Strength figured out, there is also little risk of overwriting an important move, or of losing Blizzard soon afterward.

"Yeah, but still... whyyyy???"

Lance has two lv-56 Dragonairs and a lv-61 Dragonite. At the moment, none of our pokemon are prepared for these. These Pokemon will resist our powerful electric and water attacks. In addition, Drill Peck and Quick Attack will not be too effective on Dragonite because it knows Barrier. Finally, none of these dragons know Outrage or similar moves, eliminating the possibility of a lucky Bird Jesus Mirror Move.

And we're not going into this anywhere near full health. We're gonna have half our Pokemon fainted, Bird Jesus and AJ at half health and poisoned or some crap like that, and we're going to still need to make it out well enough to face Gary. Blizzard is the perfect solution to this problem:

"Okay, so we have a problem, but will this really help? Can't we just grind it off?

This should probably take 1-3 hours if it goes decently, depending on whether we go Democracy and how lucky we are. This time, however, will be much better spent than grinding a few levels.

1. Blizzard is Super Effective against the Dragonairs as well as Lance's Aerodactyl. Additionally, Dragonite takes 4x damage from this attack, PLUS Barrier offers no resistance to special attacks. Blizzard or Ice Beam on Helix/Fonz/Air Jordan are the only conceivable moves that could take down dragons this efficiently.

2. It has 120 base power and 90% accuracy in Gen I, making it the single strongest move in the game (excluding Hyper Beam, Self-Destruct, and Explosion, which are less viable for other reasons)

3. It offers a feasible secondary attack for the Pokemon that learns it. This will help us through Victory Road where every PP will count. Not to mention the fact that 90% of Victory Road's wild Pokemon are weak to Ice. Similarly, for the unspeakable challenge that the Elite Four presents in general, we will need a diverse range of powerful attacks.

"So when are we going to do this?"

Picking up the TM should be a simple task. It's impossible to miss it since it's right in the middle of our Pokemon Mansion route.

As far as when/if we actually teach it, it depends on what the hivemind wants. Hopefully right after Operation Surfboard (the plan to teach Surf to Helix and Fonz, as well as Strength if possible.)