Congrats on your upcoming ED-picking up my E90 at the Welt last October was one of the coolest things I've ever done. Here's what I experienced.
1) Should I request PS2s, or will they be the default tires?
I tried to request PS2s however, my dealer told me that they had no control over what tires the factory installed. When I first saw my car at the Welt, I was a little disappointed that it came with Contis and asked if there was any way possible to switch to PS2s prior to taking delivery-unfortunately there wasn't. My friend picked up a near identical E90 on the same day & got PS2s & wheel locks so I guess there's a little luck involved. The Contis were actually decent but I ended up switching to RE-11s whan I got new rims.
2) Will wheel locks be installed from the get go?
3) The ED confirmation says standard floor mats (not M ones) will be installed in Europe. I'm fine with those, but will those come back to the US?
I received standard floor mats but negotiated m mats with the dealer upfront (so now I have two sets of mats)
5) I live in a no front-plate state - the PCD won't drill in a front holder will they? The Euro front plate is supposed to be taped on according to what I've heard.
I was worried about the same thing. My dealer advised me to take the US Spec holder (which should be in the trunk) with me when dropping the car off. This will avoid the prep guys at PCD/port from "proactively" installing the front plate mount. While you're at it, take the warning triangle from the trunk (as this will most likely be taken) and leave a large note on the dashboard asking the delivery center not to take the Euro plates (ED shipping company no longer allows you to take the plates off as souvenirs prior to shipping)
Hope this helps.