grammar - Nuance of ないようにしないと and a potential relative clause

I have a following line from a manga

せめてお願いをする / あの子たち以外には

できるだけ迷惑をかけないようにしないと

which of course means punctuation is lacking, hence / to indicate where a line break was, which might indicate a comma.

Context: This is being monologued by a person who intends to take something from one of "those girls" which is of course likely to involve all of them and get a fight started.

So here (and before a bit) she is I think deciding that she wants to do things as peacefully and quietly as possible so not to bother other people.

What I'm wondering is:

1) ないようにしないと. I know しないと is one of those "must" forms only with the negative state missing which is common. So that alone means "must do". I wonder what additional meaning is added with the inclusion of ように. With just ように I'd say that segment means "So that (people) other than those girls aren't troubled". Adding しないと seems to turn this just into "I must not bother other people as much as possible". I'm just then wondering why use ように at all? Couldn't をかけないと have conveyed the same? Or in other words, is there a more nuanced meaning added with that ように?

2) せめてお願いをする, does this describe the girls? Or is this maybe a separate sentence segment. Is this: "I wish at least, not to bother anyone except those girls as much as possible" Or is is something like: "I'll at least ask the girls (for what I need), and endeavor not to bother anyone else".

Sorry for the two-fer :D

Answer

ようにする means "to try to ～", "to behave in a ～ manner", "to lay out a situation so that ～" etc. For example, 会う is simply "to meet", but 会うようにする indirectly refers to some action/effort/thoughts that eventually leads to the result of 会う (e.g., making an appointment).

• 迷惑をかける
  to bother/trouble


• 迷惑をかけるようにする
  
  to try to bother; to behave in a troublesome manner


• 迷惑をかけないようにする
  to try not to bother; to behave in a trouble-less manner
  (or "to avoid doing anything that may end up bothering them")


• 迷惑をかけないようにしないと。
  I must try not to bother them.

お願いをする modifies あの子たち, but せめて ("at least, ...") adverbially modifies 迷惑をかけないようにしないと. If I could put a comma in this sentence, I would place it right after せめて.