The spike in RPM is probably due to the engine starting while the starter was still engaged... the high pitched noise is often indicative of the starter being engaged with little to no load. Had the engine been running before the starter was engaged you would have heard that wonderful ginding noise we all love so much... I wouldn't worry about this one occurrence but do fix the root of the problem. I suspect the cold start injector's tip is probably clogged.... if it is it is often just caked with oil and grime and can be washes with a semi soft brass brush and some carb or brake cleaner.
The temperature thing could have been due to the coolant leak, definitely keep a close eye on it. The temp gauge in the MKIII isn't a linear display and the center actually represents a broad range of temperatures... if it finally jumps above the halfway mark, the temp has increased a significant amount. There are a thousand possibilities for why this happened, but as you're having one known problem with the system repaired now, you should wait and see how it behaves afterward. Just keep a close eye on it and if it does jump again (for no reason... if you're racing ant it's 110? outside, that's something else) then stop the car and let it idle until the temp drops; try not to ever let it remain in an elevated state. How high on the gauge is too high isn't something I can tell you though.
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