I had a similar experience years ago when I tried to put together the items for a PSK. What I finally came up with and Doug expounds on his web site is the 7 groups.

SIGNALING
EMERGENCY DEVICES
SHELTERAND PERSONAL PROTECTION
MEDICAL
WATERAND FOOD
PERSONAL SUPPLIES
MISCELLANEOUS / MULTI-PURPOSE

Or in my words and order of importance...
Fire
Water
Shelter
Knife-Tools
First Aid - Medical
Signalling
Food

Compared to your list then whistle and signal mirror would be lumped into signal group. Depending on your particular slant you may wish to include either, both, or something else in your kit.

Similar statement regarding water and water purification. Ideally we would like to carry at least some water but that may not be practical in an Altoid's tin. Instead a compact container and a method to collect and purify water would be an alternate choice.

Shelter can include clothing, debris hut, tents, tarps or a wide range of possibilities. A PSK probably would not contain any shelter but a larger kit may include something as simple as a trash bag or space blanket up through a tent.

Food is bulky, heavy and has a shelf life. Most kits instead include methods to gather food. Snares, fish hooks, directions for deadfalls and snares, etc. Larger kits will include some long term shelf life products that are low volume, high energy. Food is generally considered not as important since a body can exist without food for about 3 weeks. Assuming a short term survival situation, food is not the most important need for the first couple of days. Granted you ability to function diminshes the longer you go without food. It is also a big phsyicological boost to have adequate food sources.

Fire. Matches, flint and steel, MFS, lighters and various fire starters all have their place. What you choose to include will vary. The general thought is that disposable lighters or other one-handed firestarters seem to be the first choice followed by the alternatives.

I guess map, compass, rope would all fall under tools. Useful items but are not required to survive. They open options to make self rescue easier.

Insect repellent is a nicety in my opinion. You can smear mud over skin and it will keep insects from biting.

Sunscreen, raingear, extra clothing would be covered by Shelter.