Alright, scenario number 1; I've got a focussed practitioner who specializes in Biomancy or Self-Enhancement Spells. How do most of these work if I want to; temporarily increase her speed/strength or alter her senses? I can see a few ways to handle short term boosts, what if I want it to last longer?
Biomancy is a tough cookie to deal with, mainly due to lack of evidence from the books. We've seen a couple of examples of minor healing stuff, and we know that the specialty exists, but we haven't really seen a powerful practitioner let loose with the specialty.
The best way to deal with any kind of intermediate questions about magic effects is to ask yourself, "How would I mechanically represent this in the game according to the given constraints?" and then talk about how many total shifts you'd need to bring about the effect you wanted. The only other thing it says in the Biomancy entry is that the body might not be designed to handle the kinds of alterations you're doing, so you have to take that into account too.
So, let's look at a Might enhancement. You have no Might, and want to be able to use a Might of Superb for a certain length of time. So that's a 5-shift complexity ritual right off the bat. That's going to tax your body, and system logic suggests you'd express that as a consequence. You want to have this enhancement for a whole session, so we assume the consequence is a self-inflicted moderate one. You have a physical stress track of 3 boxes, and a moderate consequence is worth 4 stress, so inflicting a moderate consequence on you takes 7 shifts. You're looking at a 12-shift ritual. (Maybe, if you're generous, you don't charge for the stress and only ask for the 4 shifts, and it's a 9-shift ritual. It's up to you. I'd charge the 12, but whatevs.)
Now we can tell a story about how you prepare for this and do it. Make sense?
Scenario number 2; A Sorcerer decides that containing a lightning bolt in his hand for awhile might be more useful than tossing it as a single strike. How could this be played out to; add damage to his Fists/Weapon attacks (would it just be a weapon of the power value, aimed with a relevant skill?) or keep it contained for an exchange or two to be released when the timing is right?
Hm. So, again, we're talking about setting constraints - no one's ever done this in the books, and all Jim's prose seems to suggest that when you summon up the power for the evocation, you have to let it out somehow, directed and basically in a straight line toward your target. (I know, there's an edge case in Small Favor. Don't look at me like that.)
Assuming you're fine with it at your table, I'd just pay damage and maintenance and have done - you want a Weapon:3 "electrical aura" or whatever, and you want it for the next 5 exchanges, you're looking at an 8-shift evocation. You wouldn't get the benefit of using your Discipline as an attack roll because of how you're describing the effect, though - in that case, you're just controlling the manifestation of power. In fact, you wouldn't even be able to damage anyone in the same exchange you cast the spell. In subsequent exchanges, you'd have to roll Fists or Weapons to connect, and it'd just work like a normal weapon.
Scenario number 3; Harry gets sick of his poor Latin Skills landing him in awkward situations with the White Council and develops a spell that's literally nothing but a translator. Do I just treat this as a spell that boosts his Scholarship, does it add an Aspect, what?
If it were me, I'd honestly just let you do it, and then I'd have other wizards in the scene make fun of him for having to use a translation spell to communicate with them instead of learning Latin like a real wizard.