For 4. above. It has been argued that there are a number of differnt "types" of time. There is the percieved time you mentioned at the top, and there is for want of a better word "intrinsic" time. There is a belief among some physicist that not only are there gravitons or gravitational waves (as per photons and light waves) but also intrinsic units of time and temporal waves (AKA star trek). That the 4th dimension of time is both particulate (as in photons and gravitons (which are yet to be proved
) and "experiential", simialar to our familiar 3 dimensions. If this is the case then as gravity may well have an effect on time, based on similar principles to the effect it has on photons.