I think this question has been asked before, and answered in some detail.
Simplifying things greatly - you have a 2" lift - if you fit rear springs intended for a 1.25" lift (and as I mentioned in the other thread, OME does not market their springs as providing a specific amount of lift), then the back of your car will be lower than it should be - if you fit rear springs intended for a 3" lift, then the back of the car will be higher than it should be.
How much lower (or higher) will depend on a number of variables, for example, how much load you have in the vehicle, and how much load the springs were designed to handle (OME specifies their springs based on "intended additional load" - or - the load you intend to add over the vehicles' "normal" loading).
Perhaps another option would be stock replacement springs with spacers from a 2" spacer lift - at least in theory, you'll get the same amount of lift that you had with the Calmini springs.
Question - are you replacing the rear springs because they are broken or because they are sagging? If they are sagging what is the likelihood that the front coils may also be sagging and also need replacement?
Selecting replacement front coils would present more of a challenge because the Calmini kits come with replacement arms which adds another degree of variability to the equation.