I'd make sure you get some good quality arbours. Make sure they are Rated to 12K as this is where your machine tops out. If you are going to use sidelock arbours, I'd keep to under 8K. The shop I'm in uses ETM holders from Iscar ER32 and 16 collets. They work pretty good. Cutter wise we use solid carbide exclusively. All we cut is aluminium and a bit of Copper. We'll stick to Garr and OSG pretty much, because they are readily available here. They both make tools for cutting stainless as well.
A good Vise is necessary, Kurt or Gerardi. My preference is for the Gerardi.
Even with the probe, you'll want a good set of measuring instruments. If you are running short run parts, the probing time will cut into your cycle times quite a bit.
The machine I run has tool breakage, and I've taken all those cycles out of the part programs that I run on the attended shift, because it can add up to 5 minutes of added cycle time to the parts. When I'm running a run of 100 parts, that's a lot of time.
I wouldn't go hog wild buying stuff to start. Get a good set of holders, then buy as your jobs demand it.