Points 1, 4, 5 address your system instability. Point 4 imo is a long shot. I have never known anyone who had to do that.
Points 2, 3 will make your machine faster. Installing an SSD will make your system hugely faster, additional RAM much less so (and will be a bit expensive with a laptop). I would recommend not bothering with RAM. But in any case, sort out the instability first.
The laptop spec is high. There is no reason to be replacing that for another three years unless some super amazing tech comes along that you really need.