The silver foam pad is just a grounding connection. Just re-form it as best you can; it will almost certainly still do its job, and besides, there are at least four more to do the job, so it's highly unlikely to cause you any problems. Likewise the tear in the tape is inconsequential; it's not going to hurt anything the way it is.
It's always advised to plug the screen in and reassemble far enough to power it on before you glue down the screen anyway, and by doing so you can verify that everything's working correctly before you disconnect the battery again and apply the adhesive.
Long story short (or TL;DR as they say), you're fine; you haven't done any serious damage and there's no reason the phone shouldn't work perfectly after you put it back together.
A fellow Pixel owner
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