I was planning making my other character a Mage with Charisma, then get Jahan for crafting and Madora/other henchman as a tank. Would that be a viable party?
Yes, but in that light, on easy and normal difficulty you literally can not go wrong. Play hybrids, experiment, try stuff out. Jahan is air+water so you might want to put the emphasis a bit more on fire+earth on your main mage. Pet pal on a mage is perfectly fine (if that character will also be the barter bot then skip know-it-all just as Eidolon suggested.)
Wouldn't I spread my maincharacter-mage too thin by adding points to Charisma?
As Eidolon suggested you can keep some +charisma gear around, however I haev to admit that in my 2 playthroughs I haven't thrown a single point into charisma on my main characters, I used a charisma hired henchmen and more often I could just not be bothered to go through the proces of picking henchmen up, removing a party member, throwing henchmen out, picking party member back up. So I "missed" a lot of gold, yet I did not ran into any gold issues. If you do aim to have your mage be mister or misses charisma then you might want to give him/her a few of those +3 abilitypoint books as in all fairness a mage uses a lot of skills on elemental schools and personally I used those books to give my 2nd main leadership 5, as that is is a huge increase to well... roughly everything combat related. Leadership 5+ is probably best on Jahan as your own mage will deal more damage that way, however just make sure it is not on melee characters or ranged physical damage dealers as endgame mages are not that impressive and will basicly act as paramedics with some aoe/single target damage spells so you want to maximise the effect of leadership on non casters imo.
Is a 2H tank viable, or is a shield a must?
On easy and normal, yes it is viable, so is a shield a must? No.
Even on hard a shield is not a must, aslong as you know what you're doing. You're basicly allways weighing surviveability versus damage and killing opponents faster means less damage aswell. On hard that is a bit trickier as they have more hitpoints so sometimes having a shield+1hander can be convenient. Also keep in mind hitting with 1hander is 3AP and 2hander is 4AP (as long as the item is equal or lower level then your character.)
I read that you're best off using your maincharacters for crafting. Is that true?
Basicly... yes, since your main characters can get the pragmatic trait and therefore allways have 1 crafting more. You can look at it this way: Crafting to 5 costs 15 ability points, if you have 1 from pragmatic it will only cost 10, if you also happen to have scientist it will only cost 6. That being said because Jahan has scientist he is a pretty good crafter and without any mods crafting higher then 5 is not really needed. I found a mod somewhere that fixed missing recipes and some other stuff without being horrible imbalanced and in the players favor, with that mod crafting 5+ matters as there are some minor bonusus for having crafting 5+. However with crafting 5 you can make all that you want and you probably want to look for bracers and a belt that give +crafting/blacksmithing and use them on your crafter so that you're not spending tons of points in crafting. Jahan with 2 points in crafting + scientist and belt/bracers can do all that you need.
Finally, I'd like to take Pet Pal (not sure about the name, the one that lets you speak to animals) on my Ranger. Would that diminish my combat potential?
Depends on the level you are taking it, basicly upto level 7 I think all ranger talents are fairly locked up (when not taking into account lonewolf otherwise they are locked up till 11) So I suggest taking pet pal on the mage because as the game progresses mages get kinda whacked with the balancebat and aside from know-it-all, far out man, glass cannon mage talents are kinda iffy... so you can easily take pet pal with a mage and not lose any damage potential.
Hope it helped, remember play and do and take what you like, I tend to try and min-max things upto a certain point which is not allways the way of the most fun. The journey is part of the adventure and you can learn a lot of things by failing and in the worst case scenario you can use a savegame editor if you feel really unhappy with your choises so you do not have to start over.
With kind regards,
Rashar.
