If the examined powder is fine enough to be analyzed by TEM, the all mentioned properties (grain boundaries, fine structure and interfaces) may be characterized by this technique.
Yes you can see the grain boundaries through TEM. with the help of selected X-ray analysis (part of TEM) yiu could see the structure size wheateher it is in fine or coarse.
More over the interfacing functional group on particle surface could be seen in TEM. The dislocations can be foundout by High resolution TEM images and selcted xray diffraction patterns.