Bathrooms in older homes often have concrete and steel mesh behind the tiles (against the 2x4s). This makes demolition a challenge but you tackle it as you would an elephant - one bite at a time. Use your pry bar and keep working at it. Leverage is your friend!
I hear from so many people that they have difficulty making a final colour choice based on the little swatches that are available. I always recommend that you narrow it down to two or three options and then purchase a quarter litre of each. Try them side-by-side on your wall in an area with good light.
To properly enclose an existing metal support column, you need to first ensure that the existing column is level and adjust if necessary by tapping on the leveling bolts (usually found under the caps at the bottom). Next, box the column in by custom cutting plywood (you want only one plywood piece per side). Screw the plywood in place but, as seen in the final picture below, add construction adhesive and caulking on the corners. Note that when you place the first piece onto the existing metal column, you need to use self-tapping screws.
In the before picture below, you can see that in this kitchen, the spacing around the window is uneven. One one side, there is a sliver of wall but on the other, the molding runs right up against the cabinetry. Tile is therefore required on only one side of the window. You need to carefully plan your time placement prior to starting to lay it. Since you will be laying partial tiles to the side of the window, there will be joints in that area. For continuity, you also want to avoid joints and any tile slivers on that side all the way up to the ceiling.
In the project below, I found the centre point of the wall above the window (between the two cabinets) and used the centre as a starting point and tiled out in either direction from there. In that way, I could control the size of the tile that was placed along the edge of the wall, making sure that there were no unsightly slivers there.