1st question:
the non fate heroes will have static status defined by the current administrator of the war. the magi, is completely customizable by you. waste your points in whatever you like, pick the spells you think you need and good luck. no changes after the profile is done thought.
2nd question:
magus can actually learn a set number of spells. the number increase after each round( a full holly grail war ) of war if the magus is the winner. you can take any kind of spells and choose a school for specialization. dont worry i'll make a guide upon then.
3rd question;
the damage for a spell depends on the effort put on casting it. The Definition of the damage is applied over a grade + effects. so lets say you waste 30% of your mana to cast a fire bullet.
wating 30% of mana should consume about two circuits of a average mage to instant cast. your effort is 30%mana, the circuits dont count in the end for spellcasting. the spell should have a attack ranking of D- (100mana/15rankings=6.6mana spent per ranking, but we make it to 6 so things can get a bit easier)
heres a table of spellcasting ranking calculation
(considering 6.6% of magic per rank not considering the decimal numbers. )
EX = only with external sources of magic that can sum up 300% mana.
RANK A+ = 100%
RANK A = 93%
RANK A- = 87%
RANK B+ = 80%
RANK B = 74%
RANK B- = 67%
RANK C+ = 60%
RANK C = 54%
RANK C- = 47%
RANK D+ = 41%
RANK D = 34%
RANK D- = 27%
RANK E+ = 21%
RANK E = 14%
RANK E- = 8% or bellow
as for the duration of effect/wound depends on what and who took the damage.
lets say a magus takes a A spell damage and it rips his/her arms off, this damage is permanent, and wont heal. not even if the person gets a prosthesis.
but a wound like a scratch, it would heal depending on the mage's brute endurance.
but wounds do not heal during a battle, they take time to heal after a battle, a scratch heals right the next day, but, a bullet wound lets say, should take up to a week of rest.
effects depends on the magical energy of the target, brute magical energy. the higher the magical energy of the target the more resistant it is to effects.
the effect is also defined by the spell rank, so the higher the rank the longer the effect will linger, some effects might be permanent as some curses are, but most they can last up to 15 turns. 1 for e- and 15 for A+