Ok, I think I might be able to clear this up. The factory tweeters on most Accords and Civics are simply spliced into the speaker wiring... not complicated at all. The tweeter has a high range capacitor built in.
How do I know this? I happened uopn this the day I bought my 04 Coupe.
Step 1) Buy Car
Step 2) Drive Car to shop
Step 3) Open tool box and proceed to remove all stock stereo
Step 4) Sell stock stuff on Ebay in "never used" condition
As far as them fitting on to the other doors......
Here's a novel idea. Take the tweeter pod and hold it above the top of the door apnel on the recipient vehicle and using your factory installed eyeballs, LOOK and see if it will indeed fit.
...Do I really need to go any further with this?