It should be fine.. The cage may be a bit wide and your shifting will suffer and become clunky, it may require some finer tuning to not drop the chain, it might be totally fine ... You really won't know until you try. As for the overshifting comment, if your limit screws are set correctly it should be mechanically impossible for that to happen.
Same with the rear, as long as your shifter matches your rear cassette there shouldn't be much of an issue. But derailluers are cheap and if your spending money on everything else it's not worth the messing around trying to get mis-matched stuff to work smoothly.
I don't know whats avail RE chain guides, but you can get one's that fit between your BB and the shell.