So the text of Deep Shadows states that "Characters with a range value greater than 6 have a range value of 6 instead" and that "Powers and Team Abilities that affect characters up to 10 squares away affect characters only up to 6 squares away instead."

It seems to me I'm still allowed to TK an adjacent character up to 10 squares away anyway, since the power isn't reliant on the TKer's range value (e.g., Kilowog has a 6 range but can still TK 10 squares out), and that since I'm not trying to hit somebody with TK from long range, but instead TKing somebody right next to me, that I don't have to worry about the whole "Powers affecting characters up to only 6 squares away" stipulation either.

Can anyone clarify?

I would say that TKing one of your figures falls under the "Powers and Team Abilities that affect characters up to 10 squares away affect characters only up to 6 squares away instead" rule.

As the game currently stands, everything is limited to 6 range right now with Deep Shadows/Darkness. Actual ranged combat, Outwit, Barrier Placement, and even TK. I believe they used the specific wording they did so that in the future, a possible power/feat/effect could be made that avoid the limitation of Deep Shadows/Darkness; there currently is no such thing, though.