I commute in Seattle in the summer 2.5 miles one way with some hills on a 3 speed, nearly 50 lb bicycle (vintage Raleigh DL-1 lady model). With a 24 tooth rear sprocket, I have lowered the gearing adequately to make it up most hills I encouter without walking, even when carrying loads. You will for sure need a step through bicycle considering you wish to cycle in skirts. Generator lighting is a nice thing to have as is a good braking system for rainy conditions. These are two things my Raleigh does not have, and I am considering spending a lot of money to address these issues because I love riding my Raleigh so much-- and would prefer to ride it year round. Personally, I am not so in to coaster brakes, but then again, they would be an improvement over the rod brake equipped DL-1 and its relative the Flying Pigeon. Mainly, I like to back pedal when stopped to get my foot in the correct position to start again, and this is not possible with a coaster brake.

Theft: I don't think a girly dutch style bicycle would be a huge theft magnet even if expensive. If the frame is secured with a good mini U lock, you should be fine. Maybe I am being naive, but this is my attitude with my own girly bikes that I put a lot of money into. A poorly secured (eg. with cable only) bicycle or some fancy road bike is more likely to be stolen from what I observe.