So I'm going Eldar. Will my character be locked into just being a scorpion? Or will I be able to change it around?

No locks, like in Planetside 2 you will be able to change your class to any other on spawn.
You however will be locked into your starting subfaction of choice (until new ones come out, at which point it was said that you would be able to swap if you want to, to those new ones that is).

Just to clarify, your character is locked to the subfaction its created in (e.g. Ulthwe, Iyanden), but you have 4 character slots on buying the game and can purchase additional ones as microtransactions.

You have complete freedom of classes within those subfactions, although you're effectively locked to the class and loadout you choose all the time you're alive on the battlefield. Some classes may not be available to certain sub-factions (e.g. Black Legion can't field Dark Apostles) in line with the lore.

Sweet. Thanks man!

Note that at the moment, you can change your characters subfaction. Or at least I was able to.

At the moment the characters are just glorified name claims, that's likely why.

Waaait ... When was that confirmed ? It's been stated that we're following 6th/7th edition, why would the Black Legion not have access to Dark Apostles ?

I'm confused

It wasn't, I picked a bad example. I keep forgetting just how freaking broad the revisions made the Black Legion.

Word Bearers won't have access to Bringers of Despair would have worked better as an example.

Ah, no worries mate

I wasn't being a dick, just thought I missed something.