We do, yes… we run several networks larger than that and know of many other users that do the same. Everything on your list is fine, except CPU temperatures - Xibo doesn’t monitor that.
The database size can grow if you have proof of play stats enabled - however we do ship a stats archiver in 1.8 which solves that issue.
The performance of the whole system is directly tied into the collection interval of the players. The lower the interval, the more load.
1.8 uses push messaging to remove this problem, you can set the collection interval to something very high and then have new information pushed to the players via XMR.