[Oglemi*]

When dealing with dual types, you should write it as the following:

Rock / Ground type or Rock / Ground typing.

Notice the spacing around the slash as well.

Never use a hyphen; so Rock- / Ground-type and Rock / Ground-type are incorrect. (Technically Rock / Ground-type is correct, but it looks bad, and Rock / Ground type just looks more visually pleasing. So, deal with it I suppose.)

EDIT:

Speaking of hyphens:

It's early-game, mid-game, and late-game with the hyphen. Not early game, midgame, or lategame, or any iteration of that.

This is already in the OP, but I figured I'd reiterate again.

EDIT2:

Again on the subject of hyphens:

Never say something has been Swords Danced or Choice Banded. Use Swords Dance-boosted or Choice Band-boosted with the hyphen connecting the boosted. Ex: Charizard's STAB, Solar Power, sun-boosted Fire Blast hits like a truck.

EDIT3:

Finally, we need to decide how we're going to spell subpar:

According to sources on Google, both subpar and sub-par is correct. I like the hyphenated version myself. Is this something we want to standardize or just leave as is?