Sorry if this is an easily answered question but I couldn't find a definitive answer myself.

Do we know exactly what dice come in each starter. Eg I've seen it confirmed Finn has only 1 die in the Rey starter meaning you can't play elite Finn without buying two or getting lucky in a blister.

I've never played any card game collectible or otherwise so I'm just trying to plan my entry.

1 of each plus a few blisters seems solid but presuming I enjoy the game as much as I think I will, am I going to want to double down on one or both starters at some point or is that just overkill giving way too many un needed spares?

Its just a matter of preference. In the Rey starter Rey has 2 Finn 1. Then 6 more dice, if you got 2 starters that will give you 2 copies of those 6 plus your second fin die. Of those 6, only 3 can be found in boosters, the other 3 are starter only, same with the Kylo deck.

For me I'll get 2 starters of both Kylo and Rey. Then I'll have 6 rares I'll hope to not get in the boosters.

Finn does not come in booster packs, so the only way to play him will be to buy a 2nd starter.

We actually cover this question and talk all about the starter decks in our podcast. I recommend checking out https://community.fantasyflightgames.com/topic/232012-knights-of-ren-episode-103-begin-your-journey/ to answer your questions. And feel free to let us know if you have any more questions.

Finn does not come in booster packs, so the only way to play him will be to buy a 2nd starter.

This was one of my last questions, actually. Thanks. I'm used to the "2 core" thing from FFG but I was curious if they were going to buck the trend this time. 2 of each core set it is, then :/

List of the two starters

https://community.fantasyflightgames.com/topic/226748-complete-decklists-of-the-two-starters/

Finn does not come in booster packs, so the only way to play him with 2 dice will be to buy a 2nd starter.

Statement corrected.