Probably very similar to the N8 in all of those respects. Although I did hear some of the lower spec S^3 phones may have more RAM if they don't have an internal 8GB (or more) mass drive to demand page to; apologies if I am using wrong terminology but I am sure you get the idea. Not sure if the C7 has a mass memory or not - probably does.
You mean MicroUSB and it's not surprising at all. Cseries devices are intended for emerging markets where sometimes not everyone can charge their own phone all the time. Since there are already so many devices in these markets that use the 2mm charger, they choose not to switch it up.