You can compare devices on GSM Arena or Phone Arena. I can't post links yet, so the following is the best I can do:
GSM Arena dot com/compare.php3?idPhone1=6294&idPhone2=7815
Phone Arena dot com/phones/compare/LG-G3,LG-G5/phones/8347,9819
You can't install apps directly to an external SD Card. Free up some space in your internal storage, install the app, then you may be able to move it to SD.
What apps have you installed recently? One of them are are causing it. Do a scan with Malwarebytes Anti-Malware if you're not sure: play.google.com/store/apps/details?id=org.malwarebytes.antimalware
I didn't know there was a "Classic View", but the tabs auto-hide after the page loads. If you have Jetpack installed it will use it automatically. You can verify that by going to Settings, it appears right above User Agent.