Not really much to say here. The animosity between Nephrite and Evil Mercury vaguely reminds me of the hatred between Kunzite and Evil Endymion in the anime. Vaguely.

As with Jadeite, the reawakening of Zoisite is original to the manga and the anime. In both of those, he died and stayed dead. (He did appear later in the manga, after the Dark Kingdom arc, but that's not really relevant here.) Zoisite and Kunzite's memories of the past, and their actions with regard to Mamoru, are also original to PGSM.

Like pretty much everything in this episode and the ones preceding it.