Confirming speaker sizes and install

[Spykce]

Alright so I have been searching for hours and feel about 99% confident I just want to confirm what I am thinking here. I have a non-bose symphony system I am planning to pick up:

4" speakers for the door
6.5" speakers for the rear
1" tweeters

First off are the sizes correct? Crutchfield says that no tweeters are a direct fit but from past posts on this subject 1" seems to be the size to go with.

Second: For installation I am under the understanding that I will need to make an adapter for both speakers to change the mounting configuration. This isn't an issue for me. Also the rear speakers have the amp however a write-up shows how to swap factory plugs as well as the amp. At this point the speakers should all hook up without any other wiring correct?

As for the tweeters the ones I am planning to pick up have a integrated crossover, these should simply "plug and play"? Any fitment issues or wiring?

I'm not planning to upgrade the head unit right now, however from previous posts it seems that this isn't an issue with a non-bose system, correct?

Thanks to anyone who can help.

[a4_Fitted]

Basically what you wrote seems all correct.
Be careful on the install. Some speakers are not a direct plug and play.
splice or use connectors.
I would get a new head unit or at least an amplifier for better sound

[Spykce]

After I did some more research on the speakers I was looking at I decided an amp would be best, as well as a HU. I'm holding of 'till spring I think. The stock system doesn't bug me really.

[kovalevandrew]

I changed my OEM sound the moment the freeway plan was up.
All Alpine now, sounds WAY better than it did before.