A) Well I looked around a little bit and there seem to be i think 3 primary concerns:
1-how the program they have suits your interest
2- financial need
3-rep of the university
(practically speaking 1 and 2 should be your priority)
1-So, first thing I'd like to ask you is how sure are you that you want to do engineering? I said I wanted to not knowing what exactly it is, but because its something I've been doing for a while. My freshmen year I experimented with Ec and Biology. At the moment I'm back to engineering/computer science. So if you are not so sure, then Colgate may be the way to go. It does not have engineering but it does have Computer Science, Math and Physics so those are at least in similar subjects. Computer Science could get you into some what engineering like jobs, coding and stuff, but Math and Physics would be good for more research oriented stuff. Are you sure you want to do research? Personally I feel like engineering is more practical because you build stuff (although you can do some research) but pure sciences are more research oriented like working in physics labs and doing theoretical stuff that could be later used by engineers to make things. So those are the options at Colgate, which perhaps you should take if you are uncertain about what to do. Liberal arts environment will help you figure out what it is that you want to do and you could later do masters in it (although for engineering it is better to have an B.S. than an A.B)
If you are certain you want to do engineering then Lafayette is the way to go. Harvard is liberal arts so I experimented. It does not have the best rep for engineering but its is at least accredited so I could take the risk. Lafayette is has a B.S degree not just A.B in engineering so that is good. You may want to ask them if it is ABET accredited, that's a board in america that sets standard for degrees I think. But it seems like a good program because they have specific degrees within engineering and not just a general engineering degree.
2- seems like both colleges provide need-based aid which does not affect your admission. Apply for aid and see who gives the biggest proportion.
3- Rep wise. Yes, Colgate is better. That is why you should consider how much you like engineering verses other sciences or the humanities.
As far as other wait-listed colleges are concerned, some but not all I believe will have aid policies that affect you admission or depend on your foreign status. I think Princeton, Harvard ki tarhaan, is need-blind: as long as you get in, they'll give you aid according to your needs. Duke I am not sure off. It is not need blind, so being an international asking for aid, affects your chances of getting in. But perhaps if you do get in, they will give you as much as you need. Northwestern probably doesn't have as much aid to give but their tuition will be less too. So apply for aid, ho gaya so ho gaya.
So I can't tell you yahan jao because it is a personal issue. Get advice from tonnes of people aur khud decision lo takai baad main life mein you don't blame someone else for persuading you in anyone direction. Inshallah where ever you go you will do well. A lot of college is the experience you get from it and that is something you make for yourself, regardless of what college you go to.
You should get in touch with the college people and ask them any questions or concerns directly. Do it early so they have time to respond.This might help:
http://www.lafayette.edu/
http://www.colgate.edu/
Challo ok. Take care. Hope that helps. Good luck!
