Question 1) Who do you think the starters will be?
Take into account that Legends Arceus had NONE of the Diamond and Pearl starters at the beginning, this leads to a chance of giving previous starters some new forms.

Here’s my picks;
1) For Grass - Meganium
Meganium could benefit from having a new final evolution and massively from a potential mega, that’s too hopeful though.

I’m thinking the new form could be Grass/Fairy. I know, quad poison weakness but the benefits and new moves Meganium could learn would help a lot

2) For Water - Blastoise
Blastoise on their own a strong defensive Pokémon but what if we either double down on his defensive style or switch up with some offence, perhaps.

Offensively I’m thinking of Water/Fighting
Defensively I’m thinking of Water/Steel

I can see it working for him in either style.

3) For Fire - (Not sure on this one) Delphox?

I’m not too sure on who the fire type one could be but all I’ve got in my mind is one of the starters becoming a Fire/Poison type. Any one think of any other starter that could be a Fire/Poison type?

Question 2)

With the return of Mega Evolution, who do you want to see for new Megas? Here’s a list of the ones I know who would benefit greatly from one;
1) Arcanine
2) Luxray
3) Flygon
4) Milotic
5) Florges
6) Mightyena
7) Vivilion
8) Pyroar
9) Octillery
10) Noctowl
11) Heatmor
12) Durant
13) Claydol
14) Gogoat

Any other Pokémon do you think would benefit from a Mega or any of your favourites you’d like to see get one?

7944423
Regarding the 2nd question... I'm hoping for a Mega Roserade :3

7944423 I'm agreeing with this choice for the starter trio. It just makes sense.

As for the Megas, I think it'll be from Pokemon that are in the X and Y regional dex. So The Arcanine suggestion is out. I'm hoping for Flygon and Lapras, along with maybe Lanturn, Trevenant, Gourgeist and Hawlucha.

7944423
For the first question, let me just say which Pokemon I think will not be a starter: Charizard, because the Kanto starters already got Mega forms, and despite the memes, I highly doubt Game Freak would dare to make a Mega Charizard Z, or any Mega Z for that matter. They don't love the iconic fire lizard that much.

As for the second question, I'm hopeful for a Mega Flygon. However, I'm afraid the new Pokemon designers won't make a Mega that'd fall in line with what the person who originally designed Flygon, Ken Sugimori, would have in mind.

In my opinion of the first question: I think it would best to improve the worst starter of each type and improve them in some way. For example: Meganium is consider to be the worst grass starter. The way I would improve it is to first give it the Fairy type, give it the Regenerator hidden ability, and redistribute some stats to improve its defensive power. Emboar is consider to be one of the worst fire starters. The way I would improve it is first swap the Fighting secondary type with something like Steel, redistribute stats with a greater focus into its speed and make it a physicals sweeper with a new physical attack. Inteleon is one of the worst water starters in my opinion. How I would improve it is first give him the Poison typing and give it a new poison move that always crits. It can still use the Sniper hidden ability as to triple its crit damage.

As for Mega evolutions, I would love to see a Mega Nidoking and Mega Nidoqueen form.

7944423
I know I'm late to this, but I think Delphox(and the other Kalos starters) needs a Mega Evolution, not a regional variant. As for what Pokemon I would hope to get a Mega evolution, aside from Flygon, I think Goodra or even Noivern would look sick