New here, also new to Budgie BUT not new to Linux, nor Ubuntu [been using since Dapper Drake days] Still, this is sort of a “newbie” type question [mainly because, before now, I’ve not had a desire to tinker this way]
I have Ubuntu Budgie 17.10 installed. I know Budgie is currently built on top of Gnome  [gtk] and that it uses LightDM, specifically “Slick-Greeter” as an overrlay for the Display Manager/Login Manager/Greeter [know the technical term is Display Manager (DM) but really, I personally feel Login Manager is a better description lol]
The thing is, Slick Greeter is so barebones and I want some tweaks to it. [Specifically: Changing from Military Time (24 hour clock) to am:pm clock, removing the accessibility and keyboard layout icons and having the user[s] Display Picture/Profile Picture show up on the login screen.
I found the “settings” in the dconf editor, but they are so few and none address my desires. So I am wondering … can I safely switch to like GMD3 or something for my DM?
I am inclined to say yes for GDM3 but probably NO for any KDE/QT based ones [as those libraries may fight].
I ask because I am new to Budgie and don’t know how intertwined Slick-Greeter is to Budgie … So thoughts?