***WARNING: Following this won't get Taron all her poses in the gallery but you'll get all the scenes in P.A.N.D.O.R.A.***

First things first, if you don't have all the scenes before the patch then you may need to start from scratch. If you do, it should be simple enough to get them by playing each waifu to get enough PP.

If you didn't have all the scenes then you'll need to make a new game.

The first thing you'll want to do is complete the main story. Go to the quest log on the bridge and follow the main quest line. Along the way, or even after the story, do the side quests that have the catalysts for the manticores. This will get you access to purchase all the scenes.

Here comes the grind. After you've done the story and have all the manticores, do the remaining side quests until you have enough PP on that waifu to purchase all her scenes. Then swap to a different waifu and keep doing side quests until she's done. Be sure to do the systems that don't have any side quest in them. They'll still have some ground/space combat in them. For your last waifu, use some gifts at the bar to get her the last rank of devotion needed.

Side quests give double exp so be sure to do them on someone who still needs 2+ devotion.

Your level and devotion should be the same if done correct:

DEMI - Devotion = 33, Remaining PP = 20
Lily - Level = 22, Devotion = 30, Remaining PP = 1
Killi - Level = 20, Devotion = 27, Remaining PP = 1
Elaisha - Level = 17, Devotion = 22, Remaining PP = 1
Taron - Level = 11, Devotion = 11, Remaining PP = 1

Follow this and you'll have all the scenes in patch 0.4.0.