1st....The codpiece quest. I got it but now island says it needs to be bigger magically I have no idea where to go..Shes hottest in whole game in my opinion..2nd where can you meet the new centaurs with names. I've searched and searched
Once you acquire the codpiece from the Outpost and talk to the Cleric again. It will tell you to "enhance magically" and I believe there's a quick snip it in there about bringing to the Witch. So just travel to her cottage and get the next part of the quest.
As for the Centaurs with names that's only possible when you have the EQUESTRIAN "skill" to 3 and are defeated by a centaur.
That depends on what moves you're using I guess. On my warrior run while in combat I'd start with the Armor Crusher move until the chest armor is gone and then use Overrun. And of course whenever your stability gets low (i.e tripping) switch to a defensive stance with something like Combat Guard to regain stamina/stability to start another round of attacks.