I know it doesn't involve your listed information, but just in case it helps this is the easiest way to detect the respec that I have found.
PHP Code:
public void OnPluginStart()
{
HookUserMessage(GetUserMessageId("MVMResetPlayerUpgradeSpending"), MsgHook_MVMRespec);
}
public Action MsgHook_MVMRespec(UserMsg msg_id, BfRead msg, const int[] players, int playersNum, bool reliable, bool init)
{
int client = BfReadByte(msg); //client that used the respec
}