For your question number one look at Table 4.5 item 31. Any change in groove type constitutes writing another WPS.
Question #2: If you test on any thickness below one inch the welder/WPS is only qualified for 1/8" up to 2 times the thickness of the test material, but if you test with material 1" and over it is qualified for 1/8" to unlimited thicknesses.
EDIT: see table 4.2 for WPS qualification ranges of thickness and Table 4.11 for the welder qualification range of thicknesses.
I'll take a stab at the other question in a little while...I have to run UT some joints in the shop right now.....