Greetings Patrick,
I'm no Avast expert, but I can tell you that MS Edge has yet to support 3rd party extensions, so the password manager or anything else for that matter, won't work in Edge. From what I read online, MS tried to have support for extensions ready for the TH2 (Threshold 2) release, which is build 10586 (available now to fast-ring insiders), but that didn't happen. The word now is hopefully we'll see Edge support for extensions in the next major upgrade - code named Redstone, due maybe late spring 2016.
MS has a love affair with Edge. It was built from the ground up as a closed system, i.e. closed browser, and runs really well on a decent machine under Windows 10. Microsoft rightly figures what could really screw it up is to open it up for add-ons, plug-ins, extensions, what have you. I suspect, just like getting a universal app into the MS store, there will be a pretty strict signature or certification process to go through to allow your extension into Edge. Hoops to jump through. That said, even when Edge eventually does support extensions, I don't expect to see the flood-gates opened. It's gonna take time...
So that's edge. Now then, as far as Internet Explorer 11 as included in the current release of Windows 10 pro 64bit... Imma thinking it should work. I know my RoboForm works there, ands that's important since Avast partnered with Siber System's RoboForm as the core of their password management offering. If RoboForm works, so should Avast password manager, aka EasyPass. I'll try it here and see what I can find out.
I'm a long time RoboForm user, but brand new to Avast. I've been doing some digging/playing around with Avast the past couple of days and I have noticed one thing... It seems the version of RoboForm Avast is using is at least two, and maybbe three versions old compared to the current version of RoboForm. RF's current version is 7.9.16.7. In order for me to test Avast, I have to disable my current version of RoboForm. That's the test I'll do on IE 11 and get back to ya. I used to like IE, but they could never patch all the security holes fast enough. I'm not a huge fan of Google, so I shy away from Chrome. Firefox was my favorite flavor until I stumbled upon Waterfox, which is run by just one guy. He uses Firefox and recompiles it for maximum 64bit performance. Waterfox is only available in 64bit flavor. It's my default browser.
I do like Edge, but I can't use RoboForm with it, so right now it's just a play toy.
Lemme see what I can do with Avast and IE 11.
Cheers from bayou country!
Mr. Joey