JustThisOne

Cutting the connection to the grail is irrelevant (there is no connection in the first place, they are only connected to their masters), the grail helps summon the servants not maintain them. See Gilgamesh and Rider (post HF) for examples.

If we are talking about a fight, then Tohno will just get his ass blitzed. Most servants will just laugh at any attempt that Tohno tries to hit them.

HF mostly, surprisingly the back story Kirei gets in Fate/ Zero does not add to his character in any way, its mostly just fluff.

Surprising considering how old the game is.

Its more like a parallel universe,the events that occur in F/HA are real but occur in a different universe. However there are only a few characters that can perceive these different universes.

You are not alone.

In F/HA it follows none of the routes, it is more of an amalgamation of all the routes in which no fighting ever occurred (I would get into the details but then it will just get confusing). HF is no more "canon" than Fate and UBW. Actually in TYPE-MOON all routes are equally canon, even bad endings are canon.

I would argue that HF had the best plot, but I don't want to discuss that.

Sakura hate from UBW? She had next to no role in that route.

Granted, but you do not know how to use your TARDIS and you are hunted by the Daleks for the rest of eternity. I wish I had solar panels.

Granted, but it turns out that Santa is a Lovecraftian horror. I wish I did not have to walk to work tomorrow.

http://www.ign.com/articles/2014/09/05/hatoful-boyfriend-review

Umineko definitely. Awesome story and OST.