1.1: We'll see. Main approach should be: "add what is really useful, skip else". I'd just keep what has been extracted for now, and maybe add more later if useful.
1.2: Keep UnitTests.xml as example and boilerplate within the extracted framework: Many extensions can just use this set of parameters unchanged.
1.3: I'd try to streamline the naming and location towards our existing conventions as far as possible: Use Classes and Resources folders. This however may raise some headaches for the acceptance tests, the path finding in codeception is somehow funny.
2: Yes. I'd prefer to move "TYPO3\CMS\Components\TestingFramework" towards "TYPO3\Components\TestingFramework"
3: I'd prefer to not have the components directory directly in the core but to split it once and move to an own repository within github.com TYPO3 space. Same goes for similar "extractions" that may follow, like maybe the cache framework.
4: No opinion here.