Nice work. A few comments on the four solved so far.
this indeed refers to Nigel Short, the English grand master, and blasting the enemy center with C4. Hence 1. c4, and the English opening.
giuoco piano, not pianissimo. It's a form of the Italian opening - hence Ciao.. and quiet game as the hint suggests. And finally, hidden as anagram in ciao-i-go-upon.
The Reti opening, flexible and a form of asking the opponent how he wants to play so you can choose something else. It was hidden as anagram twice, tieing+prone and inept+ignore. Richard Reti, obviously.Sweet treat for the German Zucker-Tarte, hinting at the other name of the opening, Zukertort opening.
, indeed From Gambit. It replies to the the Bird's Opening, aka Dutch attack, so I used a Dutch translation / counterpart to Henry Edward Bird, the master who played it. The great Dane is Martin Severin From for whom the opening is named. From is the opposite of to, and firm tag mobs is an anagram of From's Gambit.