A 10W charger from Apple will definitely charge the original iPad mini (which came with a 5W charger) faster than will the 5W charger. The circuitry inside the original mini will allow faster charging than what can be provided by that stupid 5W charger. Apple just went cheap.
Generally, speaking, for USB devices, you can swap chargers provided the plug fits and the charger can provide the current needed by said device. I do it all the time. Just keep in mind that if a devices can use 2A at 5V and you use a charger than provides 1A (or less) at 5V, then it will take longer than it might if you had used the original charger.
Oh...and Apple is prone to not let other chargers work with their devices, so I usually use my Apple chargers on other devices and not the other way around (so the answer to the OPs question is very likely NO). You can buy third-party quality chargers than can charger both Apple and non-Apple devices.