Ok don't quote me cause I don't have my books in front of me right now. I would say no due to that u don't normally meet the prerequistes for game rules. As for if I was running a game, I would allow them to take the feat but it becomes inactive when u take that item off. But I do hate when people base their character and their characters effectiveness on gear, since u don't see someone go into a depressive state and kill themselves cause they no longer have their magical armor (unless of course it was a family eirloom of somekind or the key to saving the universe.)
1. Yes you can. That is what it means to be a permanent bonus. If, for any reason, your stat ever drops below the requirement, you lose the bennefits of the feat. If the feat is a prereq for more feats, you lose those too. At least until your stat gets back up.
If a Duelist's dex score drops to 11, does he lose access to all his class features when he loses access to the prerequisite feats for the prestige class?
Correct me if I'm wrong, but I could have sworn that this very annoying issue was changed in some manner with Pathfinder. I recall 3.5 functioning just as Caineach stated, and I could have sworn that Pathfinder changed it somehow.
Or perhaps it was just the interaction with prerequisites due to how ability damage changed? Not sure, hmm.
This has been answered before. Lots of times. Here it is again:
Prerequisites
Some feats have prerequisites. Your character must have the indicated ability score, class feature, feat, skill, base attack bonus, or other quality designated in order to select or use that feat. A character can gain a feat at the same level at which he gains the prerequisite.A character can't use a feat if he loses a prerequisite, but he does not lose the feat itself. If, at a later time, he regains the lost prerequisite, he immediately regains full use of the feat that prerequisite enables.
Permanent Bonuses: Ability bonuses with a duration greater than 1 day actually increase the relevant ability score after 24 hours. Modify all skills and statistics as appropriate. This might cause you to gain skill points, hit points, and other bonuses. These bonuses should be noted separately in case they are removed.
That second quote might not be 100% clear so let's clarify: If you wear an item that gives you a permanent bonus (it's permanent if the item does not need to be activated for a specified duration of effect), then once you wear such an item for 24 hours your ability score goes up.
It's important to note that if you have a STR of 10 and someone casts Bull's Strength on you, then you still have a STR of 10 with a temporary value of 14. If you put on a Belt of Giant Strength, then for the first day you have a STR of 10 with a temporary value of 14, but after the 24-hour waiting period has passed, you now simply have a STR of 14, and as such, you qualify for any feats that a guy born with a STR of 14 could qualify for.
If a Duelist's dex score drops to 11, does he lose access to all his class features when he loses access to the prerequisite feats for the prestige class?Yes.. a Duellist who loses his Dex is in major Hose City
It's what made the... Reaping Mauler? class in 3.5e so terrible. The Reaping Mauler was a grapple-based prestige class. The class, as a prerequisite, required them to have the feat Clever Wrestling, which, as a prerequisite, required them to be small or medium sized.
But, since all they do really is grapple and pin and hurt things by grappling them, and they can only grapple creatures that are medium or large, and even then grappling was all opposed checks and they had penalties for trying to grapple larger creatures, eventually they would have to be made large either permanently or temporarily so that they could enjoy size bonuses to grapple and the ability to grapple larger creatures.
But, the moment they were made large so that they could grapple huge creatures, they suddenly became absolutely crippled... because they could no longer meet the prerequisites of Clever Wrestling, and therefore couldn't access any of their Reaping Mauler class abilities.
EDIT: Question: If I'm say, a fighter with 13 strength who has Power Attack... if I take 5 strength damage, do I lose access to the Power Attack feat? If I take 5 strength drain, do I lose access to the Power Attack feat?
EDIT: Question: If I'm say, a fighter with 13 strength who has Power Attack... if I take 5 strength damage, do I lose access to the Power Attack feat? If I take 5 strength drain, do I lose access to the Power Attack feat?
If you take damage, then no, you're fine. Consult the rules on ability damage and you'll find that ability damage doesn't actually knock off your ability score; it's more like the relationship between your max hp and your current hp. Ability drain is a different story; in that case, you'll lose Power Attack until its cured, because it actually does reduce the stat.