imo ,limiting startup activities "can" be beneficial. but not always.
May i ask where you came up with this one? imo if your hardware can handle it, then disabling these Visuals won't make a difference in performance, It "Can" make a difference, but not always. When you play/open a full screen app/game then they are disabled, while your full screen app/game is running.
Disabling Virtual memory is dangerous, as you never know when you might need it, sides, you can't truly disable Virtual memory, as Windows is a Virtual memory based os.
System restore is a basic safety net, i never disable it as it has saved me many times because of some bad update/change, so i leave it, if it takes too much drive space, then reduce the amount of storage it uses. It creates a restore point before a wu takes place, and before installing applications.
Certian antivirus apps are heavier than others. so simply use a lighter one or tweak the settings of said antivirus to make it lighter if you can.
I agree with "Each one has it's own pros and cons"