Which of these use Windows 8? The W8 store looks quite promising right now since it's not so saturated.
This might confuse you even more but Windows Phone 8 is for the Windows Phone Store, and the Windows Store is for tablets, and computers running the Windows 8 OS.
Do I need a Wifi connection to use them with Construct 2, or is there another way to test my games on them? I don't have Wifi, I'm on cable.
No you don't need WiFi if your going with a phone instead of a tablet since smart phones require a data plan wether that be month by month billing or prepaid. But it is highly recommended to use WiFi whenever possible or your phone bill could end up being hundreds, if not thousands of dollars per month.
If your on cable you should have a wireless WiFi router it's that little box that connects your cable to your computer. If you don't have one for some reason just ask your cable provider they usually include them with there service. If not there pretty cheap to buy.
How do you develop for these platforms? Is it a case of developing on your PC, uploading them to a site then connecting with the phone/tablet to the site?
Iv been developing for Android. Each platform is different, and has one or more different options to choose from for developing. I develop on my computer then export as a CocoonJS export. Then I upload the exported .zip file to DropBox. From there I open it with the Ludei CocoonJS Launcher (it's an app available in the Google Play Store). It allows you to test, and debug your game on an android devise. After all that and my game is ready I then upload it to the CocoonJS Cloud Compiler on Ludei's site, and compile it. Then I get a unsigned APK file in my email from Ludei.
After all that then I Create a keystore file, sign my .apk file, zipalign my .apk file, and then its ready for upload to Google Play Store.
The first time through may seem like a painful process but it gets easier.
Here are some links to things you might want to read over before you choose what platform you want to develop for:
How to make Android games
How to preview on a local network
How to export to CocoonJS
Create Android Games
Android games with CocoonJS
Some Windows Phone 8 info:
How to make a Windows Phone 8 app
Plugin Windows Phone
Here is some info about a new accelerated canvas option under development for PhoneGap:
Pender Project - Android Accelerated Canvas
Pender Android for Phonegap Cordova
Some people have there C2 games in the BlackBerry 10 World store but I can't find any info on how they did it. Also Construct 2 doesn't have a exporter for BB10 or officially support it yet. But this thread would be the one to watch for future info:
BlackBerry 10 and Construct 2
I hope this helps answer a few questions, and doesn't leave you even more confused. lol