All strainers will come with a seal and nut for standard hook ups.
You can go cheap, or nice. We only install the nice ones. I either get the baskets with the pin and ball, or the twist down type.
I'll be installing a new Blanco SS kitchen sink and need to get strainers for it. I noticed the flange that the strainer sets on is shaped like a funnel but the strainer assemblies that I've seen at the big boxes have a flat nut or a flat collar with screws. Do you have to use a special assembly with this type of flange?
What you are calling the "funnel" type installs with a smaller nut at the bottom, as opposed to the much bigger nut that requires huge channelocks or prefferably a special tool. I think the funnel is easier to install, and the other type's nut goes bad faster. Terry is right about the connections, of course. All standard stuff for hookups.
not a licensed plumber
What you describe is the same situation you would have with a cast iron sink. The void in the funnel gets filled with plumber's putty and then you tighten the drain in place, UNLESS you have a Blanco or similar drain with a "bolt" inside it to hold the pieces together. Then you just use the bottom rubber gasket to seal it and nothing on the top.