Troubles with US Cellular S6 Edge

I've been doing my share of reading and have come to many dead ends. Here are my troubles with my recently acquired second hand US Cellular Galaxy S6 Edge:

-Bootloader: I've looked in many websites trying to find a way in which I may check the status of my bootloader. I don't know whether it's locked or not and would like to have it unlocked if possible (OFW 6.0.1)

-Unlocking bootloader: just to be sure I was unlocked I tried using Crom services to unlock my bootloader (the apk) but it crashes before opening. I also tried to find the app in the Samsung App Store but it just won't show up.

-Flashing firmware and downgrading: I haven't found any concrete information as to whether it's possible to flash firmwares from other carriers and or downgrade to a lower android version (marshmallow to lollipop) and if so what the requirements are.

I would appreciate any input on these topics. Thanks a bunch! :highfive:

App permissions troubles

Hi, I've got a Honor 6, version H60-L04, recently updated to Marshmallow, EMUI 4.0, not rooted.
At the end of the installation I noticed a problem with the apps that need permissions to access to the gallery, or the microphone, etc.
I gave'em those permissions, in the Authorizations menu in the app options but it appears an error: "Display overlay detected. To modify this setting, you need to disable the display overlay in Settings>App. Selecting "Open settings" then, I've been redirected to a menu which doesn't show neither an Overlay setting choice, nor others applications' setting choice (e.g Whatsapp, Shazam).
In the settings, there is only one overlay setting, in the section "Developer Settings": "Disable Overlay HW", but having it set or not doesn't solve my problem.
What can i do? At the moment I can't neither send nor receive pictures, audio, etc. in Whatsapp and Telegram, I can't shazam the music with the app and so on...

Camera troubles with Android N?

Has anyone else had problems with the N6 and Android N? I frequently use the "click the power button twice" method for launching the camera, and it can get very slow launching (as compared to Marshmallow).

What I've ended up doing is reducing the megapixels for both video and pictures down one notch (to 5MP and 720p), and that seems to have helped greatly. Curious if anyone else had any suggestions.

Cheers