search for photos imported from Photo Stream

no - you can make smart albums based on the camera - If you are using the auto import then your events have Photostream in them so you can search on that

No idea in the world what a BKM is

When you import photos into iPhoto they are automatically sorted by the sort criteria you set in the view menu

FOr more information you must actaully provide details about what you have and what you want to accomplish using english words

LN

All photos from the My Photo Stream go into a monthly Event. If you sort your Events by Date - Descending the most recent Events will be at the top of the Event window. The monthly Events will look like this:

OT

Photo Stream pictures are automatically given the keyword "Photo Stream".