I'm booked on a Q200 next month. The only available option for the first row is 2B. Do they block 2A? I am currently in 18B. Rows 3 and 4 are "blocked" (highlighted in blue, but are unavailable). The flight search screen shows 2A, 3A/B/D and all of row 4 are unoccupied yet row 18 is grayed out.

What's with the seat map disparity?

Also, SeaGuru says that the bulkhead seats have immovable armrests that may reduce width. Is this true? I'm a rather wide person that will fit, but would rather be more comfortable.