From my experience, LR Frieza will launch a super attack every other turn.With three attacks per turn, and a super attack every other turn, expect to be able to tank without healing for two turns.Then you have to get the appropriate medals to Dokkan awaken that character.This step gets repeated a few times, so pay attention.
As we briefly touched on above, I do have a specific team that I recommend: Whis (Leader), Super Saiyan Vegeta (Angel), Vegeta (Kid), AGL Paikuhan, Baby Vegeta, Super Strike Vegeta, and LR Goku (Friend). With LR Goku as both your friend and your leader, your team easily has a base Ki of ATK.
For a more complete list, check out the Dokkan Battle Wikia page listing freely obtainable units.
The great thing about LR Frieza and Summit of the Universe is that there is an abundance of AGL characters available to use.
This is only really an issue if the player has not taken advantage of any of the events in which characters are freely obtained.
Strike Event characters, for example, are free to join the battle.