2019.2.0a14 VS Unity Tools problem, Android SDK and Package manager immutable folder warning.

I didn't find these mentioned anywhere so I'll describe them.

1. Small annoyance when building for Android. This warning pops up:

Completely new install. Performed a cleanup of remnants SDKs in AppData before that as well. Still there even when building a new project.

2. VS 2019 and 2017 Unity Tools refuse to recognize Event Functions (Awake(), etc.), they are absent from autocomplete. (Visual Studio Editor package updated)
This used to work fine, I think in 0a12 and earlier.

3. Original project was dragged through upgrades beginning from 2018.3. When some plugins gave unrelated warnings I've uninstalled them. But got stuck with a bunch of these warnings, same ones, several at a time.

Reinstalling everything cleanly didn't help, deleting cache and Library didn't help. I had to clone repository and rebuild from that. That did the trick. Then was able to remove packages without errors.