1) Can you enhance a figures RCE if they are using trick shot? So the damage is 5, 2+2 for RCE +1 for enhancement.

2)Can a figure outwit another figures stealth even if they are adjacent to each other, and the stealthed figure is in stealth.

3) also if a figure is adjacent to a stealthed figure can they outwit say super senses, even though the figure is stealthed.

4)Does Super senses doge splash damage from EE, and do inv or imp prevent splash damage.

thank you much

Yep. (No different than using Enhancement with RCE normally.)

Nope.

Outwit requires LOF and stealth will treat the LOF as blocked.

See above. (Isn't that the same as question 2?)

Super Senses can be used to cause any attack to miss. This includes splash.

Invulnerability and Impervious reduce damage dealt. Splash damage deals damage to characters so both of those powers (and Toughness) work.

Not on topic, but your post made me think this. Flyers adjacent to non-flyers can still range each other. What if one is stealthed? Can the other guy only close combat now?

If a character is stealthed then a LOF cannot be drawn to them. So a ranged combat attack would not be allowed. Close combat would be allowed against an adjacent character. (Stealth has nothing to do with close combat.)