I'd forgotten about the multi-tile thing... you
should still be able to attack is you manually use the attack command (pull up the combat menu -- you
really want that hotkeyed if you're using a reach weapon, anyway) and then... 'l'ocation? I think. Lowercase L, in any case. Free move the targeting cursor on top of one of the tiles. It should take a swing for you at that point, and hit, if my memory of the process is still good.
Feats for monks? M'not actually sure I'd
take power attack as a starting feat t'be honest. One of the
ones I won with a ways back didn't take power attack at all (note: This was an older version -- I'm not sure if chi strike is still bugged or not.). Also you totally wouldn't want to go multitude anymore.* Power attack's probably not the most useful of talents for a monk unless you're intending to pick up the kick feats, at least if you're going unarmed -- you're not going to have the highest BAB (and thus tohit) score in the world, which means you won't be getting all that much out of it.
PA's good enough if you're going strength monk (and possibly grapple), though, instead of dex (which goes weapon finesse, instead). Big deal about going finesse is dex is going to be helping out your (desperately needed) DC, which is nice, and it synergizes with lightning fist (and you'll kinda' badly need the increased attack speed if you're eventually going unarmed -- this is less true if you're going with weapons or grappling primary, of course).
Lightning fists and fists of iron are nice starting ones (though in retrospect somewhat contradictory to my earlier "don't punch things for a bit" statement. Hrm.), sneaky's good if you're intending to stealth (obviously), expertise is apparently sexy according to me from years back. Dodge is naturally useful, as is run (though run is possibly somewhat superfluous in the face of your class based movement bonuses. Still, faster is better.). Of course, the fist stuff is meaningless if you're going weapon-monk, who probably wants cleave and
will take that power attack.
Really, the question is what you're trying to
do. Feat choice is going to change based on if you're going unarmed, unarmed with a grapple focus, armed, or... something else. Dodge and expertise are probably the only two starting feats I'd say are unilaterally useful on a monk. Maybe run. Later stuff is later stuff -- fist monk picks up special punchy stuff, grapple monk picks up grapple stuff, weapon monk picks up normal face-beaty feats ala barbarian, etc.
*
No one wants to primary worship the multitude -- lay worship, sure (s'really random, but there's always that chance of /detect monsters/ or whatever and the minions can be useful.), but that "healing potions piss them off" thing makes 'em pretty much unplayable as a primary god. Only characters that might even remotely want to try would be someone with access to minor and/or major drain (they don't actually want to do that, no, but they're less crippled by it).
--
As for stairs spawning in dangerous places, other than making the stair tile
itself safe, if that's possible, I really hope that feature sticks around. It's incredibly atmospheric to occasionally have a staircase that ends hanging over a chasm, or on top of lava, or in the middle of a river or whatever.
Does suck to go down and immediately drop/fry/drown, but it's a beautiful mental image.
And yeah, the stair-surrounded thing is a glitch in the map generator -- you're notice you can actually see through one of the surrounding walls. Been meaning to drop off a save showcasing that behavior, but have been distracted and whatnot.