Probably they are, but «This is my plan» roughly corresponds to Russian «Это мой план», so this course wants you to use «Вот...» for «Here's...» and «Это...» for «This is...».
Да, в этом может быть и есть смысл, но это не должно считаться ошибкой v placement test
i guess, 'here is my plan' is more like proposing your idea to people rather than owning it by saying 'it's my plan'.
We will take the back door since we can't go head on our only option is to flank them. When we are behind them, I will take the one on the left, you get the one on the right. After they are both down the heavies will make a frontal assault, after they find out their flanks are exposed, they will retreat. We cannot let them regroup with their reinforcements, so we will cut them off there. After that, we should have reinforcements for the front line. Taking the rest out will be a breeze.