Summoning Titan and Ramuh is an excellent start. Barring moments of great distress, my friend Rydia could only call upon Chocobo at first. Titan she could call if sufficiently upset, but the others came later.

[Granted, she was only seven at the time, but still.]

Thankfully, her previous stay in this world has proven that the bond between summoner and summoned is not truly cut but our temporary dimensional displacement. You should not have to forge those pacts over again.