FoxCNC1
Yes as far as the tool goes, do all operations as a separate op, you can if you want to call the same tool but with a different tool # T3 .245 & tool T2 .250 for your profile
Reamers come as HSS or Carbide, but if you are cutting plastic, then most of the time, the reamer will cut under size, so you may be better to play with your cutter/tool size to get the size hole you want
Over & Undersize & Dowel Pin High Speed Steel Straight Flute Chucking Reamers | Travers Tool There are many other suppliers as well
Bits are for drill holes woodworking/metal working, anything that has Flutes Etc for milling are called by there name Like Endmill Ballmill Etc ( Cutter ) is a good way to describe what you are using