Do I have to serve the Appendix AGAIN if it's the same in the lower tribunal?

Typically yes, but, if exactly the same, doubtful because new case style, you could ask opposing counsel if they want a new copy, and there is always the possibility or even requirement of serving an electronic copy.

Serving an electronic copy would probably be easiest & save paper.

If you are a pro-se appellant, I would encourage you to do whatever the rules technically require and focus on that rather than "being green." If there is any doubt take the most conservative and obviously compliant route. As a pro-se litigant, your focus should be on the merits of getting a valid argument to the appellate court and avoiding distractions on ancillary issues like saving paper or convenience of counsel. I say this because it becomes VERY easy to rationalize short cutting for various reasons, including expense and time, and this can EASILY open the door for technical attacks on your appeal, especially when its a "second level" appeal and typically discretionary to begin with.