Perhaps forget about the additional fleece jacket and vacuum pack a down or primaloft jacket (A compression sack will help also if you are unable to vacuum pack). These will compress down much more readily in terms of space for a small daypack rather than the bulky fleece jacket.

An insulation mat such as the Thermarest Neo-air would be useful for sleeping on at the office or outside. There are quite expensive but are very comfortable and provide good insulation from the cold ground. They pack down to an amazingly small size.

A good down sleeping bag will be half the weight and size of an equivalent synthetic bag.

It is very tricky to get what is required for a Get home or Bug out bag to fit into a day pack.

I can only just about get a Tent, sleeping bag, sleeping mat, waterproof shell clothing, 3 days food and gas stove and pot, water bottle and first aid kit etc into a Macpack Rapaki 28+

Most of the kit in my multiday daypack is based on equipment lists for mountain marathons and from tips and hints from the ultra lighters.

http://www.planetfear.com/articles/The_2009_Mountain_Marathon_Kit_List_1037.html

http://www.youtube.com/watch?v=fWbYnTRBfww

Just to add, you seem to have everything covered but might be a little lightweight on thermal insulation and food. i.e. A few extra high calorie food tins can be stored at your work place.