Heya!
Ifan makes for an awesome ranged character. I'd keep him, and add some warfare to boost his physical damage and just a couple polymorph for wings and chameleon cloak. He doesn't really need much investment in skillbooks beyond huntsman skills and a couple of polymorph.
Executioner talent is nice on him, as rangers generally need to move less than melee and when they have to, there is tactical retreat/wings/ getting teleported/nether- swapped by your support mage.
Lohse you can keep as a support mage with healing, buffs from all elemental schools + aero skills for positioning. Up to you, but investing in elemental damage books with a mostly physical damage party is counterproductive. Give her a shield and a wand (good protection vs higher elemental damage on a staff that will be of little use to you with physical party)
You can try necromancy (does physical damage) or summoning, if you want her to contribute beyond healing, armor buffs and regen, support and control. That will however, require a lot of memory slots and your hydro and geo buffs will be less effective as you spread your skills thin.
As for your avatar warrior/rogue... you gonna have to choose which way to lean. For more rogue-ish character you NEED 2 daggers as most of scoundrel skills require it, and scoundrel and daggers scales off finesse instead of str (that 2h and 1h swords do)
That said, scoundrel is GOOD for 2h character as it increases your crit damage and you get decent crit chance investing in 2h. You just wont have too many uses for the skillbooks from scoundrel if you go 2h route. Mostly adrenaline and teleport, I'd wager. So, focusing mostly on warfare, some poly (bull rush etc is nice) and scoundrel for crit damage multi and some mobility will work out good for a 2handed focus. Warfare has some great melee crowd control and some moblity as well.
If you really want to keep beast more of a rogue than a warrior, those skills will work equally well for 2 daggers as warfare adds phys damage, but your skill layout will be very different, and you will be focusing on finesse instead of str.
You can keep red prince as a second str damage dealer with a shield (or 2h) and warfare, and put some points into hydro and geo for secondary buffs and off-healing without investing into int. It would work just fine.
Or! You can switch him for sebelle (elves make really mean rogues) and make her your primary finesse rogue/thief. That would let you keep your Beast avatar more fighter-like. Or get Fane and make him your rogue (he won't need any lockpicks for opening locks)
Anyway, I am not really seeing much wrong with your characters (other than severe lack of warfare on your phys damage dealers, really

) You will notice a rather harsh difficulty bump on tactician though. So, be prepared to use scrolls/potions, off-heals and off buffs and crowd control and pay more attention to positioning than on classic...