The toilet needs at least a 3" and depending on the distance it has to travel to connect to the sewer, you might need a 4". If you use 4" for the toilet and the main drain line run, then all you have to do is make sure the pipe is in the right place and plumb. You can buy an internal mount flange and they can pour right around the pipe. There may be a reason to put a sleeve around it, and if so, then you could use an outside mount flange. Trying to install the flange now is not a good idea...it should be installed after the finished floor is in and sit on top of the finished floor. For the maximum flexibility, you want the pipe's center to be 12" from the FINISHED wall. Anything less and you may not be able to use a 'standard' toilet (although some will fit). Trying to find 10" rough toilets will restrict your choices and likely increase the costs.
Not sure about the size of the vent line required for only those two fixtures...probably a 2", but wait for one of the pros.
It is helpful to know where you are, codes can differ.