Your promos look interesting, too––glad to see you're using the new formatting!
Bring Back is an effect reminiscent of other Ho-Oh cards, with a good twist in that it's not Ho-Oh you're reviving, but one of the legendary dogs. One of the most important things to consider on EXes with Abilities, however, is that you can very easily get four charges out of it each turn. As a result, the odds turn from a 50% chance (which would be the ideal balance) to a very good chance you'll be be able to set up two of those legendary dogs in one turn (assuming you have Sky Field in play). I'd suggest making it similar to the Victory Star Ability on
Victini NVI––an Ability you can only use once per turn, regardless of how many of that Pokémon you have in play.
I like Flame Transfer. Lots of room for potential in a Toolbox deck there.
Lugia looks well balanced to me. Aqua Turbo is a name that has already been used on Palkia-EX, with a different effect, so you might consider renaming it? It's a minor nitpick, though.
Suicune, on the other hand, does look
very powerful.
Serperior BLW had a similar Ability, except that this was on a Stage 2 in the days before Forest of Giant Plants, and it only healed a quarter of the damage. Not being able to heal itself isn't even that big a drawback, since you can Bench other Suicune to heal that damage. There's also the additional problem, the same as Bring Back. With four Suicune, you can heal 160 damage each turn from all Pokémon that aren't Suicune, and 120 from all Suicune. That's a lot of healing.
Balancing for that one might be a slight problem, since I think even reducing the damage healed to 10 would be a little on the overpowered side. Maybe if you can only heal 10 from one of your Pokémon that turn?