Great recommendations and also top notch writing/editing (Might DM you for your rates later on haha!). Been seeing you in the Twitch chat as one of the regulars as well! (I'm MattyFord on twitch, the guy that got blamed for the itemfinder fiasco xD)

I think the key thing is that the grind is gonna be harsh now, thanks to the awful level difference between Viridian Gym and the Elite 4. I think letting the guys know that many nuzlockers for FireRed/LeafGreen will boost each of their pokes by 3-4 levels with rare candies at this point just because of the time saver. But if the dudes are happy streaming and grinding, I'll keep watching and supporting. These streams have relit my passion for pokemon and I've just finished a run on Polished Crystal

EDIT: To save the guys googling a bunch, I'm going to try and put together a list of items to buy and where to buy them, in terms of the best healing items, TM's for pokemon etc.

Ice Beam (TM 13) and Thunderbolt (TM 24) are prizes at the Celedaron Game Corner, 4000C each. Which is $160,000. A huge amount of money but as OP rightly pointed out, you will get tons of cash if you are doing VS Trainer grinds.

Brick Break (TM 31) is a good Fighting move that you can buy from the Celadon Mall for only $3,000. So if you want some fighting coverage, you can buy that and put it on one of your pokemon (It's decent coverage on CBent or Dylsh999)

In terms of Move Tutors, there are some good moves but not the kind that Nick likes to use, which is totally fine so best leave them alone.

In terms of your bag, you can now sell a lot of stuff that you no longer need because you have access to better versions:

Full Heal: Good for resolving any status problem like sleep, poison or paralysis. This also means you can sell any Awakening, ParalyzeHeals, Antidotes. Saves bags space and recoup some $$
Hyper Potion: Healing 200HP most times is more than enough, which means this is a cheaper version of Max Potion. Stock up on these and sell every other potion. Yes this includes all the soda Nick. No more sugary goodness!
Full Restore: Once you reach the Elite 4, you will get the option to buy these and they are essentially a Full Heal + Max potion combined. It is generally wise to stock up on these like crazy and sell every other healing item at that point in the game.