Firstly, your flight sequence is CAI-ABS-ASW? There is no CAI-ABS direct flight, would it be CAI-ASW-ABS-ASW?
Secondly, are you going to drop bag at CAI and it will go to ASW, and you go pick it up later that day back in ASW after ABS sightseeing? In this case, you don't need to look for luggage storage place at ASW.
Thirdly, my understanding is that there is no storage at ABS, but the shuttle bus can take all your belongings (important or not) with it while you are sightseeing at Abu Simbel. Or if that's the case, I'd rather check my bag at ABS for return flight to ASW before boarding shuttle bus, and I don't need to take luggage with me at all.
Bottomline, you should be fine with your luggage.
For us, we'll check luggage to ASW, and then to ABS, and we will take them with us to Abu Simbel hotel.
