Breiman, in answer to your questions in no particular order...
I can't speak much about cameras as when I'm looking for an Android device sure a nice camera is on my list but I'm not as snobbish as some Apple or Android users are. So far as the number of megapixels a camera may have, sure the more the better, but you do reach that point where the human eye - and the non-snob like me - can't tell the difference between a pic taken with thirteen megapixels and one taken with thirty megapixels. The LG G Stylo I just came off of had eight megapixels and the Moto G4 I have now has thirteen, but I'd be hard pressed to tell the difference. You may be interested in getting into the details however... I have now the Moto G4 without laser assisted focus but as I said just came off an LG G Stylo (it's a story as to why I left...) which did have laser assisted focus and I don't miss it at all... You'd think the LG would focus faster and better than the G4 and it may, but I'd never notice whether it did or didn't and don't miss that feature. However the LG did have auto-stabilization where the G4 does not, so taking a pic while moving or with unsteady hands has caused me to miss that feature on occasion. Now if the camera app in the device that you ultimately choose doesn't come with the features that you're looking for, aside from megapixel count, stabilization or some other hardware issue, there are a number of camera apps that you can choose from to replace your stock camera app. The G4 doesn't come with a collage maker for example, so I just downloaded one.
Regarding stability you ask? Well the Android OS's in devices now are very stable and I haven't had any problems with them. Sure they have their hiccups every so often such as any OS does. There's a wealth of information available at Android related websites such as this one when you do run into a problem. I've used Androidforums.com for example on more than one occasion, specifically when my Moto G1 (I've become a Moto guy if you didn't know) fell to something called a Bootloop error. I don't know how tech assistance was for WP. I know that should you choose Apple, which I don't think that you're considering but if you were to, that you'd have the benefit of dropping into an Apple store for personal help. But Android OS's are really very stable unless you specifically go messing with them.
I don't use MS apps so I can't comment. But I'd wager that MS has been working towards making their apps integrate with the Android OS world so you'd probably not experience any issues. You'd probably be able to just sign back into all your stuff and just carry on, it'd probably just look a little different app to app perhaps depending upon placement of buttons and features...
The query that I've been giving the most thought on your behalf is the query you make about having a G-mail account for full functionality. Yes, you will have to get a G-mail account when coming over to Android. When setting up your Android for the first time, or after something like a factory reset, your device will ask you for your G-mail address as part of setting up or it'll urge you to create one. Not doing so will still allow you to use your device but you'll miss out on a lot of things...
Android devices don't back up their apps, pics, contacts, music (if you use Google Play Music) to your personal computer like Apple products do through ITunes. I don't know how it was/is for WP users, but Apple users (I've got an old IPod Touch that was given to me by an Apple using relative) they actually plug into their personal computers and back up their devices using ITunes on their personal computers unless they've got cloud functionality which not everyone does. I myself used to back up my IPod Touch until I went seriously Android years ago.
Android devices don't back up to your personal computer, rather they back up to mother-Google as we call her. So after a reset for whatever reason, or after purchasing a new Android device (phone or tablet) you sign in and the device will seek out the Play store and begin rebuilding itself by downloading all your apps assuming you have the auto-download function turned on. Leave it plugged in, but I've had to reset my device on occasion and I've purchased five Android handsets through the years, once you sign in at startup you can put it on a table and leave it to download and come back to it later. You'll still have to set up settings and personal items.
Functions like Google Play Music and Google Photo Backup also use G-mail. You can have your music and pictures in the cloud so that they don't take up space on your device which can be helpful to those who insist on carrying large collections of music, pictures or videos. I don't use Google Play Music to store my music as I have a large SD Card in the device, but I do use Google Photo Backup to backup my photos. When I take a picture with my device it's automatically sent to the backup feature for storage as well as also obviously being on my device. Should my device get lost, damaged, stolen or I delete a pic off my device I regret later doing so, it'll be in the back up because I have a G-mail address.
No one says that you have to use your G-mail address for having one. I primarily use Yahoo mail - for as long as it lasts anyway as Yahoo is all but dead and has been purchased by Verizon - and my G-mail address just sits there being used by my device. You will inevitably get mail to it every so often, you'll likely be automatically subscribed to Google Groups for example. But what you're auto-subscribed to is nothing that you can't unsubscribe from. I use the G-mail app that comes stock on most Android devices (it can also be downloaded from the Play Store), but there are any number of email applications that can be downloaded from the Play Store - even MS related email applications I'm sure - and many Android devices come with their own email applications from the manufacturer. The stock G-mail application will allow you to add any email address from any provider - it's not privy to one over the other - and while I use it for my Yahoo addresses I also use it to keep an eye on my G-mail address and clean it out every so often. Whatever email application you use, look for one that'll allow you to use any address, add your G-mail address to it and then just keep an eye on it and clean it out every so often but otherwise don't use it unless you want to. Just remember what the address and password are for when you do need it lest you have to go through the reset procedure.
Let me know if you have any other questions. I'll be happy to answer or give my thoughts. I actually do like the Windows Phones. It's a shame that they never caught on as I thought that they were really original, particularly the Metro Launcher. I just think that they were to late to a world dominated by Apple and Android at the time that WP was introduced. Had WP been introduced at the introduction of the IPhone and the Android then it might've stook a fighting chance...
