My suggestions for Tanis:
Since he's a Ranger, and needs to be good as a ranger, drop his Int as low as you feel comfortable it falling and up his Wisdom as high as it will go. Tanis was a pretty Wise individual, and to make him playable, Int won't help very much. Any Warlord abilities he has will be Cha and Str-based. We already have him at 4 stats used (Dex, Str/Wis, and Cha, in that order). I think 18 Dex is great, and 16 CHA is easy since he's a half-elf, but I would bust his Con and Int as low as I'd feel appropriate, and keep his Str/Wis solid. At least go Str 14, Con 13, Dex 18, Int 13, Wis 14, Cha 16.
Half-Elf Dilletante Ability: Furious Smash (melee attack and an ally gets a bonus to his next attack and damage against the same target for a round equal to Tanis's Cha. Plus, it targets Fortitude, so even with a lower Strength, Tanis should be able to land it with his longsword.)
His feat should be Student of Battle, granting him Inspiring Word 1/day. He probably shouldn't take too many Power Swap Warlord feats, but he should definitely take the Utility Swap feat. Combat Veteran might be a worthwhile Paragon Path, though Battlefield Archer would probably be more laong hs strengths.
Firt level Rangers abilities would include Archer fighting style (Defensive Mobility as a bonus feat), At-Will Powers: Nimble Strike, Twin Strike; Encounter: Evasive Strike (useable with a longsword or with a bow!); Daily: I like Hunter's Bear Trap, but Split the Tree is always nice.
As far as gear goes, He should wear leather or hide armor, fight longsword (it's versatile, so he can 2-hand it) and carry a longbow. Did Tanis ever two weapon fight? He could also carry a dagger or a shortsword to use his powers that work 2-weapon style, just in case he needs to.
All clear here! I was away for the weekend, but I'd still be delighted to play!!! - Problem is, me very moron hadn't understood that this was a 4e game. I'd love to play, but I don't have the books yet. Could you be so friendly and help me building the character? 
