In all honesty, Team 7 is a well-rounded team comp that can work later in the game as well. I boosted them all up to 3*, and they're still quite good. It's just a matter of choosing the right talents of your Main to work with their chases to get combos.
As for talents, I think you should be running either 1/1/1/1 or 1/1/3/1. The Flower Guard ability shields only the females of the team, but think about it - you're shielding your healer (who's a bit squishy at this point) and your Main. Depending on what you're doing, the other passive talent can change, but just keep in mind what you're using your team for. I didn't choose Giant Rasengan for Main's mystery because Naruto already uses the same attack with the same chakra cost of 40 with a shorter cooldown time. Sasuke's Mystery also has a 40 chakra cost, while Sakura's is 20, and if you run Giant Rasengan as your mystery you're going to be short on chakra all the time.
As for attack order, it all depends on your opponent. Typical is to get off Main's 0 cost Hurricane Jutsu first, then either Naruto's Rasengan or Sasuke's Chidori. Follow up with what you didn't choose for third, and then with Sakura's Healing to salvage ay damage you sustained while Main attacks with Hurricane Jutsu again. Of course, if you fight people who are higher level and who can hit harder, you might want to use Sakura's Healing in the third round and then Sasuke's Chidori with Main's Hurricane Jutsu fourth just to make sure they survive long enough to attack.
What I like to do is go into the Ninja Exam and run the team on different formations on auto, just to get a sense of how the computer chooses attacks based on the timing of different opponent abilities, and then go and fight the same exams on manual. Manual is a labor of love because you have to get the timing down to a pat, otherwise you will waste your Mystery as well as chakra. However, once you do, you'll be able to outsmart players who auto and the teams you encounter in Survival Trial. It's all about anticipating what your opponent will do based on their squad, and choosing your Mysteries accordingly.