Squall, you can also get magic from item refining and fixed draw points (ICTH
). You can easily have full rounds of all the best magics at levels <10. Of course some, like Ultima, are not really attainable until disc 3 or something anyway.
And about the supposed difficulty.. it all depends. If you stay at low levels throughout the game until you have all GFs, and then power-level using stat-boosting abilities and then junction correctly you'll be as close to invincible as you can possibly be, only gravity-type damage and other defense-ignoring attacks can hurt you then. Griever's Shockwave Pulsar did <200 damage if I remember correctly. Staying on low levels in general will make the game a lot easier than it should be.
FF8 is one of the easiest FFs if you know what you're doing. If you're just playing like you would in any other FF, it will be one of the more difficult FFs. If you reach level 100 without properly understanding the junction system some level 100 monsters will literally slaughter you. The difference is insane. The possible one-hit killer Breath of a Ruby Dragon (I learnt that the hard way on my first time through, Ruby Dragons were a real challenge then) can be reduced to a laughable scratch. And if you're on low levels Ruby Dragons won't even use Breath at all.