First, the most pressing matter: To get the dash over the 'e' in Pokemon, I just copy and paste it from word (it should be in the symbols list). Not the most efficent way, but meh. Actually, I only use it in my fics. Outside of my writing, I don't bother with the dash ^^
Alternatively, on a computer using any Windows OS, hold down the ALT button and hit 0233 on your number pad. (Not the top row. The number pad. If you're on a laptop, that may overlap with some keys, so you may need to hold down an extra button.)
For a Linux computer, it's ALT U0311, using the top row. I'm not sure about Macs.
As for the ideas themselves...
An OT fic can, yes, tread in cliché waters, but it all really depends on how you do it. Yes, Thesis's guide is cool to go by, but if you've read it enough times and if you've gotten yourself familiarized with the OT genre enough to know what
is a cliché, you shouldn't encounter too many problems, I think.
An egg is an interesting idea, but yeah, I'd say be wary about what it hatches into, not so much for "this is going to be cliché, isn't it?" reasons as it would be "this is going to be Stuish, isn't it?" reasons. In other words, Eevee, Dratini, Riolu, the kinds of Pokémon you don't usually use as a starter... all might end up a little cringe-worthy. If I'm reading this right and it
is Chikorita, that's fine. In fact, I'm not sure why you have reservations about it. To be honest, there's really not enough love for Johto starters, I think. Usually, it's the Kanto or Hoenn starters that get the most love, with Sinnoh coming up behind only because it still didn't exist for as long as the others. Johto? Not so much. So, yeah, don't worry about that part too much because you're all right.
As for the Larvitar, it's an interesting concept to give what would normally be a powerhouse, eyebrow-raise-worthy starter to the rival instead of the main character, and it's very classy that you chose a starter Pokémon for the main character that would at least have a chance against the rival starter's final evolution.
I think the only thing I'm a bit uncomfortable with is the trainer's school part. A lot of people start their fics off with the kids in a school for aspiring trainers, and to be honest, I've yet to see one fic that has one that doesn't follow essentially the same kind of formula (as in, with the kids maybe attending one class, but ultimately, with the only point to having the school scenes be the graduation/handing-out-of-starters part and maybe to establish the fact that the trainers had ordinary lives before setting out). Not that I'm being negative or pessimistic already about it. It's just that I always tend to facepalm with those scenes because they feel so pointless, particularly because other than in
Electric Tale of Pikachu, it's not canon that it's necessary to attend a special school or set of classes in order to get a license. (In fact, in the anime's canon, special trainer schools like Pokémon Tech sometimes are
alternatives to trainer's journeys, rather than a lead-up to it.) It won't exactly be marks against your story. It's just something to be wary about when writing the first chapter(s) of your fic.