An ATPL skill test will replace your LPC and it will also revalidate your type rating, if you are successful.
1. Should you not pass all items of the test (i.e. partial pass or fail), you cannot exercise the privileges of the type rating, until you have passed all items - that means no flying. Have a look at FCL.1030(b)(1). It won’t affect other ratings, such as SEP, etc. The same would apply if you’d fail CPL skill test in a SEP; you wouldn’t be able to fly SEP aircraft on your PPL until you would have passed all items of the skill test.
2. Nothing, except that you will have to inform your airline about the new expiry date of the type rating, and (I think most airlines want this) send them a copy of the new licence when it is issued.