I read somewhere that loyalty is based on how many missions you have been on. Now, I could use some clarification on that. Is loyalty based on how many missions you have been on with that character, or how many missions you have been on in total?

Neither. 
 
Each character has a specific Loyalty Mission, after which, if completed satisfactorily, will give you that specific character's loyalty.

" Neither. 
 
Each character has a specific Loyalty Mission, after which, if completed satisfactorily, will give you that specific character's loyalty. "

^What he said. Loyalty is black/white, either you have it or you do not. You will get loyal characters if you succeed in their loyalty mission. If you gain their loyalty, they have a little circle under them in the team selection screen and can have their costume changed.

" @Sir_Ragnarok said:

" Neither. 
 
Each character has a specific Loyalty Mission, after which, if completed satisfactorily, will give you that specific character's loyalty. "

Oh, I worded my question wrong. I meant to ask about when the loyalty mission is activated. Is it activated based on missions spent with the character, or missions in total? "

" @Sir_Ragnarok said:

" Neither. 
 
Each character has a specific Loyalty Mission, after which, if completed satisfactorily, will give you that specific character's loyalty. "

Oh, I worded my question wrong. I meant to ask about when the loyalty mission is activated. Is it activated based on missions spent with the character, or missions in total? "

Loyalty missions are usually activated a mission or two after you have recruited someone. I guess to be more direct with your question, it's based on missions in total. So for example, if you recruit Tali, you have to do one or two missions before she asks (having her with you during those missions does not matter).

" @Sir_Ragnarok: All right, great, thanks. I was just worried that I would somehow screw up and miss the chance at getting some loyalty missions or something. I missed a lot of important or cool stuff in the first game. "

After the Horizon mission, the loyalty missions roll out with jacob, then miranda, then either garrus, mordin, jack and grunt asking you. You must do a mission or a side mission after you recruit one of the second batch of characters to get their loyalty mission. It is not that hard of a system to follow, just make sure to talk to kelly to see if anyone wants to talk to you.

i have a question, when *spoiler just in case lol* jack and miradia fight do i have to have full good/bad?