1. Start positions can be modified in a Fast Mission but would require knowing a little bit about the editor to move your airbase starting location. Basically once the mission is created, you can find your plane at airbase selected, then click and drag your plane to the airbase you want to fly from. If you do that you might find yourself far from the action, so to avoid that, in the fast mission selections menu, pick a start position on the map that is close to the airbase of your choice, you'll probably get that airbase automatically. If not then as mentioned in the editor before you fly, click and drag your flight to airbase. Instant action I can't comment on.
2. Without mods I don't think you can display current weather or METAR. So best guess here is to look for a mod that will provide weather briefing. if you flying someone's custom mission, it is sometimes standard to include weather details in the briefing. Custom mission design allows you to set weather to your liking.
3. What you want is: Show Controls Indicator
4. Don't know how to modify trim behavior.
5. For carrier ops (USS Stennis is provided : Add Ship Group in editor) you are going have to get into using the editor. Something like: Create your fast mission. Then instead of flying, click edit mission. Now in the editor add your carrier, then as in #1 above click and drag your plane overtop the Carrier you added. If you picked Start from runway it should snap to over the carrier. Now click fly mission in the editor and you have customized fast mission. Caveat. The Fast mission didn't provide an F-18 selection for me. If that's the case then create you mission using a different aircraft type , drop on carrier and then you can edit the aircraft type in the drop down on the right to select the F18. Once you get comfortable in the editor you'll be able to customize to your hearts content.