You can customize colors at Preferences – Editor – Color Scheme – Android Logcat.
Here is Darcula theme, suggested by Matouš Skála:
Darcula colors:
Debug : 6897BB
Info : 6A8759
Warn : BBB529
Error : FF6B68
Assert : 9876AA
Only show logcat from selected process is supported by default feature at AndroidStudio. If you are not satisfied with current customizations you need to continue to use your favorite shell with JakeWharton srcipt as for now.