It's really hard to say. Minato is extremely fast with his Flying Raijin and is a very intelligent fighter. But Naruto has an incredible amount of chakra, his Sage Mode, and his Six Paths powers. If Naruto can get close enough to Minato, his brute strength could overpower Minato. However, Minato's speed and strategic mind might keep Naruto at bay.
In some 'minato vs naruto fanfiction', there could be a scenario where they battle in a different dimension. Minato uses his Flying Raijin to quickly move around and Naruto counters with his shadow clones and massive Rasengan attacks. Also, a scenario where they fight not as enemies but in a friendly spar to teach Naruto some secret family jutsu that only Minato knew would be really cool.
The modern army would have firearms, missiles, and advanced explosives. These weapons are highly destructive and can cause mass damage from a distance. In contrast, the fantasy army would likely have swords, bows, and magic spells. The modern weapons would seem overpowering at first, but the magic in the fantasy army could potentially counter them. For example, a magic shield could deflect bullets.
There are many out there. A really good one might focus on the emotional reactions of Team Minato. For example, Minato might be proud of Naruto's strength and how he overcomes Pain. Kakashi could be in awe at Naruto's new techniques. Their reactions can enhance the overall viewing experience in the fanfiction.
Well, it really depends. The modern army has a structured military doctrine developed over centuries of warfare evolution. They use concepts like combined arms operations. However, the fantasy army could have magic - users. If these magic - users are powerful enough, they could disrupt modern army strategies. For instance, they might be able to create illusions to mislead the modern troops or use magic to disable their high - tech equipment.
You can try looking on popular fanfiction websites like FanFiction.net or Archive of Our Own (AO3). They usually have a wide range of Naruto - related fanfictions, and you should be able to find some with the 'Team Minato Watches Naruto vs Pain' concept.
It really depends on the specific circumstances. If the fantasy side has powerful magic, like being able to conjure up huge firestorms or turn the ground into quicksand under the modern army's feet, they could win. But modern armies have advanced weaponry like missiles and tanks. If they can quickly figure out the weaknesses of the fantasy elements, they might prevail.
Well, a plot twist could be that the modern army's weapons are actually ineffective against the fantasy creatures because they are made of some sort of magical substance that absorbs or deflects the bullets and missiles. Then, a lone scientist in the modern army discovers a way to combine magic and technology, creating a new weapon that can defeat the fantasy side. Another plot twist could be that the fantasy side has a prophecy that a group of modern soldiers will save their world, so instead of fighting, they welcome the modern army and ask for their help against an even greater evil within their own realm.
Minato would likely be extremely shocked. Naruto is his son, and the idea of Naruto attacking him would be completely unexpected. He would probably try to talk to Naruto first, to find out what is wrong and why he is being attacked.