To quote HP:MoR:
"You wouldn't go along with that and neither would I," said Harry.
"This is our world, we don't want to break it. But imagine, say,
Lucius thought the Conspiracy was your tool and you were on his side,
Dumbledore thought the Conspiracy was my tool and I was on his side,
Lucius thought that you'd turned me and Dumbledore believed the
Conspiracy was mine, Dumbledore thought that I'd turned you and Lucius
believed the Conspiracy was yours, and so they both helped us out but
only in ways that the other one wouldn't notice."
Draco did not have to fake being speechless.
Father had once taken him to see a play called The Tragedy of Light,
about this incredibly clever Slytherin named Light who'd set out to
purify the world of evil using an ancient ring that could kill anyone
whose name and face he knew, and who'd been opposed by another
incredibly clever Slytherin, a villain named Lawliet, who'd worn a
disguise to conceal his true face; and Draco had shouted and cheered
at all the right parts, especially in the middle; and then the play
had ended sadly and Draco had been hugely disappointed and Father had
gently pointed out that the word 'Tragedy' was right there in the
Afterward, Father had asked Draco if he understood why they had gone
to see this play.
Draco had said it was to teach him to be as cunning as Light and
Lawliet when he grew up.
Father had said that Draco couldn't possibly be more wrong, and
pointed out that while Lawliet had cleverly concealed his face there
had been no good reason for him to tell Light his name. Father had
then gone on to demolish almost every part of the play, while Draco
listened with his eyes growing wider and wider. And Father had
finished by saying that plays like this were always unrealistic,
because if the playwright had known what someone actually as smart as
Light would actually do, the playwright would have tried to take over
the world himself instead of just writing plays about it.
That was when Father had told Draco about the Rule of Three, which was
that any plot which required more than three different things to
happen would never work in real life.
Father had further explained that since only a fool would attempt a
plot that was as complicated as possible, the real limit was two.
The way you avoid plot holes is to have very simple plans. To be fair, these plans don't need to appear simple, but they need to have no more than two things "go right." (Incidentally, identification of these crucial points makes for excellent times for PC involvement.) Plans like you articulated in your question, the "Step 1, step 2, step 3" plans so derided by competent military strategists because they break down and are vulnerable to moments of fridge logic. As enemies are prone to think about your plans in a completely different way ... don't make them too complex.
Instead, focus on logistics. The two steps don't have to be easy, but by figuring out the logistics trail needed to accomplish them, you have all your "elaboration" and complexity which goes to support two and only two things.
From a "writing the storyline" point of view, don't write what will pass. Instead, give your NPCs intentions which will shape their actions. By giving them intentions but without locking them into step 1, step 2, step 3 plans... you allow the world to resonate to player choices and accidents.
As an additional note, use PC imprisonment very sparingly. It's generally not fun and very hard to set up without being heavy handed about it.