Hey Andres,
That sounds like a pretty solid plan. I recently moved my coaching business out of a retail-strip mall and into a hockey training facility in a local ice rink and am working on doing exactly what you are talking about. Along with running my personal training business I have taken a leadership position within our local hockey club and help coach on the ice and off the ice in the gym with teams ranging from Mites all the way up to Midget AAA. Slowly, I am implementing some of our methods, but these things take time and there are many variables to consider when conducting team training with 1-3 teams at a time. Especially when you only get most of them twice a week for 30 minutes a session. But my plan overtime is to help build the program from the ground up as the 10u and 12u kids eventually grow into 16u and 18u players. There is no doubt that getting the kids stronger and teaching them sound technique in the weight room will have a great impact on their performance on the ice, but these things take time.
I have a pretty big advantage in getting this done, as I had a reputation built with in the hockey community as I opened and ran the pro-shop inside of the rink in 2004 and managed up until leaving to open my first gym in 2010. This enabled me to negotiate good terms and come in with a familiar, respected face that the local hockey community has welcomed. But I still have to work on building it every night when I am on the ice coaching and in the weight room where I can be dealing with up to 30 kids at a time that have almost zero experience lifting (or even exercising). My plan over time is to have a positive impact on developing many of the athletes in our program and motivate some of them to push themselves to be better. And that certainly includes getting stronger as well.
So that's a bit of my experience. I would suggest talking to coaches and parents. They both have a vested interest in the players development and if they will listen, it is hard to argue with the logic of getting stronger. The two big roadblocks I can see are the people that run the training facility not being open to discussing methods that conflict with their own and the fact there really isn't much of an off-season for most competitive hockey players. You will find these things to be very challenging. I would suggest approaching the training facility exactly how you mentioned and figure out what they think about training. Ask lots of questions to figure out what they think athletes need to be working on and ask what kind of challenges they face. Let them know about the program and what kind of impact it can have. Most won't listen, but a few probably will. If you can get started with a few that is a great place to start.
The off-season is really the only time hockey players can really make strength gains. In the winter when they are practicing 2-3 times and playing 2-5 games on weekends they just do not have the energy to really make progress. If they eat enough quality food they can probably muster a month or two of LP in-season if you can teach them the lifts and get them to do them, but it will get hairy right away and you really need a coach with a lot of experience to manage that process or you are going to run into a lot of problems. In the spring/summer when most players are doing their off-season training is the window when strength should be built. I think the key is to focus time to building strength and skills in the summer, and shift to conditioning and getting 'game ready' in the pre-season.
If you are going to do this make sure you know how to coach and have some experience teaching a variety of people the lifts. There is a world of difference in doing the lifts and instructing others how to do so. If you haven't already, make sure you get to a seminar to gather experience and get to one of Nick's Coaching Training Camps as well. You need to have experience teaching this stuff and coaching if this is not going to go anywhere.
But this is a noble cause and you should pursue it. You could have a profound impact on the development of a lot of players. There are a lot kids out there that are not able to compete because they are too weak and unfortunately have no idea what a difference a good strength program could make. It is sad because every scout is out there looking for a big tough kid, who can skate and play. Good luck. Let me know if I can help at all.