I have to get to my day job for the next 10 hours but I'll at least answer the 'jumping' bit. Players always have gravity applied to them via the physics engine, so they are indeed 'held down' to ~something~ by default. There is no "floor" technically. Whenever you jump, it does pulse a linear velocity upwards to cause a jump; the arc of the jump is fine (holding doesn't produce infinite jump), the issue is pressing jump AGAIN (causing the just to re-apply). I do get hit events, but there are some catches. I cannot simply say 'am i colliding with something" because if I did, wall jumps would work, as would "ceiling jumping". I can't go by vertical momentum because vertical platforms adjust this by pushing the player up or letting them fall - plus there is a point in the player's jump that "appears" to be stopped (at the peak), which allowed for a double jump.
My solution will be to place a collision sensor at the very bottom center of the character, I just haven't done it yet.
And for the column, I'll let my artist know about that; thanks Krohm!