Just wanted to chime real quick and say that there are no guides about Pass Powers except for one video which is good enough but there isn't a written guide.
This is honestly quite fascinating. It seems like you are right, there are no written guides for Pass Powers in Gen 5. Nor does there seem to be any for the Entralink in general, or for the Entralink/Funfest Missions. How is this possible? I guess the demand for a guide for those features is (or was) never very high, and that nobody ever bothered writing one.
I searched a little, and I assume this is the video you mentioned?
I watched it and I think it was pretty good. It is fairly short but it still does a great job at explaining how you unlock more Pass Powers in B2/W2.
As for my experiences with the Entree and Pass Powers, I remember that when I was leveling up my Entree levels to get more Pass Powers (I was actually more doing it for the TC upgrade, but whatever) in both B/W and B2/W2, I never really used a guide. I never felt that I needed one. I just tried my best with the Entralink/Funfest Missions until I succeeded, and I had tons of fun along the way! I remember that reaching the next levels for the Entree in B2/W2 seemed to happen very randomly, I never really understood the principle behind it. In B/W, I remember that it was a lot more straightforward compared to in B2/W2.
Still, it is a bit weird how there's not a written guide for Pass Powers available anywhere. Maybe someone should write one? Maybe I should? It would be great to have a complete guide for the Entralink, Pass Powers and Entralink/Funfest Missions, all in one place! It is interesting how this discussion came up now, because in the past, I have had thoughts about writing a guide for Funfest Missions. However, I never got around to it due to the lack of time and interest. Not sure if I have the time/dedication to get it done nowadays either, but I'll consider doing it if anyone is interested. Maybe other players can help as well, and we can work together to get it done. Just an idea I got.
As for written stuff about Pass Powers... while there are no real guides, there are some general info at least. First, we have Serebii's pages on
Pass Powers in B/W and
Pass Powers in B2/W2. It does not mention which levels you need to be at in order to unlock the specific powers in B/W though. Then we have
Bulbapedia's page on the Entralink, which includes a list of all Pass Powers and which levels you need to be at in order to unlock them for all Gen 5 games. Or so I assume, they never specify if it is for both game pairs or just one (if so, which? My guess would be B2/W2 but I really don't know). There's also a method to exploit the Entralink in B/W in order to get high-level Pass Powers for free, I remember seeing a guide for this on Serebiiforums many years ago.
Here is the thread for it.
This might not be the guide you were looking for, but hopefully you can get something out of all of this at least. My recommendation for the Entralink and Pass Powers in general is to just play the Entralink/Funfest Missions and have fun. If you do, you'll get the Pass Powers as a bonus along the way.
I want to hunt for Level 1 Gyarados :D
Oh yeah, this too. That's another thing I like. Being able to catch Magikarp and Gyarados at any level from 1-100. Never tried it much and I have no idea why they added this to the games, but I'm glad they did because it is such a random and fun idea. As far as I know, this has only been done twice in the series. First at the Resort Area in Platinum (Magikarp only) and then at the Nature Preserve in B2/W2. According to Bulbapedia, it seems like there's a 1% chance to find a Gyarados at any level if you fish at Rippling water spots in the Nature Preserve, so basically a 0.01 chance in total if we assume that there's an even chance of finding one at all possible levels. Either way, it means that the chance of finding one at level 1 is extremely low, so I can definitely understand why you want a good Pass Power to increase your chances of finding one! Not sure if you are into RNG abuse, but that might be another way to get a level 1 Gyarados without relying (too much) on luck.
And while I'm still here, I have some more things to say about Gen 5. After making my post yesterday, I remembered a few more things I like about Gen 5 which I completely forgot about in my previous post. So here are those things:
- The Dowsing Machine. I think Gen 5 has the best Dowsing Machine in the series. I always used it when I explored new areas in the Unova games, it was just so useful when it came to finding hidden items. I think the only other Dowsing Machine that comes close to being this good is the one in HG/SS which is also great, but not quite as great as the one in Gen 5 if you ask me. Though I still think it is the second best in the series without a doubt.
- Many legendaries to catch. This is something I really like in games. It is mostly a thing for B2/W2, B/W aren't quite on the same level but still fairly good and far from the worst in the series. Either way, B2/W2 are currently tied with Platinum and HG/SS for being the fourth best in the series when it comes to the amount of legendaries available for capture. While they were tied for being the best at their time, they are no longer the best nowadays as OR/AS, USUM and S/S with the DLC are all better. That said, I still think B2/W2 did very well in that area.
- When a Repel runs out in B2/W2, the game asks if you want to use another one. This was really convenient, it saved a lot of time because in previous games, you would have to go into your bag in order to use a new one. I'm very happy that this became the new standard for the series as it continued in all games after B2/W2.
- Unrelated to the games, but still related to Gen 5. I like the B/W chapter of Pokémon Adventures. It is one of my favorite chapters of the manga, I love everything about it. I think it captures the essence of the B/W games and Gen 5 so perfectly. The overall story, the characters and the Pokémon in this chapter are just so great. I have to admit that it was the first chapter of the manga I read so I might be a little biased because of that... but even so, I think it is really great.
To put it bluntly, what makes Gen 5 special is not the major additions it has (which are... actually very few, possibly the lowest of all generations), but how it raises the level of what was already present in the game.
Graphics (with a few exceptions), sound, pacing, story, user experience...
It's the culmination of all the little refinements they had been making to the formula since Gold/Silver. It's not really a massive leap forward from the generation before it, it's just a bunch of little things done well.
Pretty much this. Gen 5 didn't introduce any new super mechanics or features, it just polished and improved upon things that already existed in the series and took everything up to the highest possible levels. I think they succeeded extremely well with it.