Welcome to the forums. You've come to the right place for feedback. Your thoughts are excellent ones. I've owned a Class C, but currently own a FW. The Class C I had was much smaller, it was a Winnebago Warrior on a Toyota Chassis. It was easy to drive, great fuel economy and at that time met our needs for room. I wouldn't worry about the decision you've made based on your needs as they are valid, but there are several other thoughts that you should take into consideration as well before you sign on the dotted line.
Storage space, as you mentioned is an issue. Where will you put the trash can? Sounds funny, but that one question by my husband on an almost purchased Class A caused us to back out. After he asked that question, I really took a look at the cupboard space. How will you pack, where will you put the toys, are you taking bikes, etc.?
Can you safely secure their booster seats? I don't think there are shoulder seatbelts in the back seats and I'm not sure you want to put one of them in the passenger seat yet.
What about how you are going to use it - all hookups or dry camping? Will it meet those needs. Hookups are usually not an issue, but water tank capacity and how you are going to cook will be if you plan to boondock or dry camp. If it only comes with a microwave and you don't have a generator, cooking while dry camping will be a challenge.
What about the warranty on the unit and the reputation of the dealership? That is a HUGE factor when purchasing an RV. I've heard nothing but good on the service and warranty on Jayco, but not much on Coachman.
Those are my thoughts, but others will have more input for you. Best of luck on your decision. Another thought too is that you may be having buyer's remorse which is very common. If you've never owned an RV before, it can be scary, but remember that there are pros and cons to everything, and the pros should outweigh the cons. RV'ing brings a lot of enjoyment, but just as in owning a car, things can happen, it's just part of the joys of ownership.