I think a few of the points you are concerned about are true about FT programs - especially about finding the career you need to move into. However, I think the offset is that maybe this is a pressure that you need, otherwise you might never make the change. Recruiting for the summer starts quickly (term starts September, first recruiting starts October - at least for IB/C and some bigger Marketing & Corp Fin, some Gen Management as well) so you need to get an idea where you want to go quickly. There is the possibility to change after the summer - I know some MBA2's who have done exactly that - but it isn't necessarily easy. However, there are people I know who have changed their mind, and they recruit more boutique. S+T for one isn't a route that guarantees offers (IB similar, but not quite so harsh in numbers, at least as a %) so there are opportunities buy side, in HF and in Boutique IB advisory, M&A coming through now, and both people who have changed their mind or a re-fixing are looking at those. The pressure on the first wave of recruiting is heavy, but the chances of getting the ideal Bulge Bracket firm are not as high as you might wish they are, even for the most focussed. I feel that a lot of people benefited from this pressure to decide, as it is something most would rather procrastinate on. We will see how the wash comes out after the summer.
As for the difference in the course, I don't think there is quite the atmosphere on the PT (not surprising), and they don't get some of the star professors at Stern (Damodaran, Silber (not sure, but think not), they do have the Engel class), but they do take an awful lot of classes with the FT class - at least on the weekday night courses, and some of the weekend as well. This is where Stern's PT gets its real value, and for the FT as well, because they can scale up the classes a little in number and breadth to allow more niche classes. Virtually every FT MBA1 I know is doing at least one class that is with the Langone students. I will be able to tell how this affects the curve only later in the semester, but you get directly pitched against students who have the possibility to study during the day (but probably don't). All the same, it points to the teaching being the same, though the learning opportunities are obviously reduced, or you are very, very tired.
I think so long as your essays fit with your wish to go FT/PT that the school will not be too concerned. They are pretty understanding, and more driven by you knowing, or at least expressing, what you plan to do. Maybe speak to them and ask - they should be pretty good about it.