1. Jiraya had info on Nagato/Pain's Realm thanks to previous incounters he had in his past life and Sage Mode, meaning Ma and Pa surveying the whole battle.
- Minato would have no way of counter or figuring out the Rinnegan's Shared Vision ability without knowing which one is the real Nagato.
2. FTG is a good Jutsu, but spamming it would be a waste of a strategy to counter the Six Realm's of Pain.
- Nagato/Pain has the Realms shared vision which is a useful ability utilized by the Rinnegan. Even if Minato was to, lets say spam FTG, Pain has abilities to counter it or if he doesn't, he can simply replace the dead Realm with his Revival Jutsu.
3. Ninjutsu, Taijutsu, Summoning are out of the question because Nagato/Pain's Realms are counter to those Jutsu such as his Absorption Technique, Shinra Tensei (All Mighty Push), Banshou Tenin (Universal Pull), Summoning Technique ect.
- It's unknown wheather Minato has Genjutsu because that want shown in the Manga/Anime.
Nagato/Pain FTW or "Draw."