It's hard to tell from the picture angle but it looks like the first and third car are identical coaches. The second car looks like a sleeper and has the additional detail of still having the lower skirting intact. The coaches had the skirting removed, which happened later in their operational lives, to make maintenance easier.
The last car is a typical baggage car. You can tell a baggage car because they usually have only two loading doors per side and no windows. This is where all the passenger luggage and some small packages that were sent by Railway Express would be carried.
In terms of value, in general terms, the older an N scale model is, the less it is worth. The N scale models of today are much better runners and much better detailed than the models of even 10 years ago. Kato always made decent models. Both of the engines are correctly numbered E-8's and the passenger cars are some of the better detailed 90's N scale models so they are worth a few bucks but probably a lot less than you think (or hope). The other locomotives you have ranged from pretty good to awful but we'd have to see pictures to know for sure. Same thing with the rolling stock. One thing you can do is check e-bay for the same items that have already sold and see what they went for. That should give you an idea of the what yours might be worth. There are also modelers here that will buy things from you but you really need to get a complete inventory together, have as many pictures as possible, and list them in the For Sale section. Other N scalers will let you know if you're asking too mch or too little.
