[4.1] When do I get upgrades? You gain two more Materia slots when you are promoted to SOLDIER 1st class. You can gain more accessory slots, two at max, by completing missions 7-2-2 and 7-2-5.
[4.2] Where exactly do I get the Genji equipment?
Genji Helmet: Libra/Zero MP & AP cost: Buy it for 1,000,000 Gil Net Shop Darkness after unlocking it in mission 9-5-4.
Genji Armor: HP Limit becomes 99999/Auto-Regen/Auto-Endurance: Achieve 100% DMW Limit. If you miss the Phoenix summon you cannot get it.
Genji Shield: Auto-Barrier/Auto-Magic Barrier/Absorbs every element/Immune to status ailments: Must acquire it from Magic Pot in mission 7-6-6. When it asks use Gil Toss, Sacrifice Punch, 99999 Damage, and Yatou Issen (Sephiroth) limit break.
From what I’ve heard. Doing this is extremely difficult and takes many times to try. Magic Punch has been suggested to get 99999 Damage. Equip the Materia called Yatou Issen to increase the likelihood of the limit break.
[4.3] Other then the Genji equipment, what are some good accessories? Safety Bit Effect: Protects from instant death. Where: Buy at Nibelheim Shop which is gotten from a treasure chest in 6-4-4, or from 10-1-3.
Supper Ribbon Effect: Protects against all ailments even instant death. Where: Steal from Great Malboro in 9-6-2.
Adaman Bangle Effect: 99999 HP Limit. Where: Finish 7-3-6 or find it in a treasure chest in 9-2-4.
Gold Hairpin Effect: 9999 MP Limit. Where: In a treasure chest in 9-2-5.
Black Hood Effect: 9999 AP Limit. Where: In a treasure chest in 9-3-3.