A moderator will need to move this to the Java SE community:
1. I imagine the last release will be available from Jan 2019 onwards (Just as Oracle still lets you download old public archives), but no public updates will be provided to that version.
2. OpenJDK 8 and Oracle JDK 8 are near on identical - you'll see some differences in Swing applications and Sound drivers but for all other intents and purposes they're effectively the same.
3. Most browsers are disabling Applets