^
not a general consensus .. just a starting point. Where to HP the guitars can depend on so many factors ... how many rhythm tracks, tuning, arrangement, cab / head used, how it was mic'd , etc ...
also depends on the style but for the most part, its not a bad starting point. You want some meat on the guitars but not too much actual low end ... that is the bass' job
yes, 200 IS too high, if that's where you're HPing your main, heavy rhythm guitars, something has either been done wrong in tracking or your listening environment is FU'd
as for the bass question .. I have no idea if he's running two or more bass tracks. I'm going with the assumption that he's using one, therefore I mean HP on the bass (or low cut, however you wish to call it). I would allow everything Higher than 50hz to Pass the filter, cutting away everything below it (to start with) and then find a spot where the kick thump isn't eating too much and give it a small bump (2db to start, medium to wider Q) and just see how it all sounds. It may take several more adjustments but these are only meant to be a starting point in guiding him (and you I guess?) into bringing in more bottom end meat without clouding anything up