I am extremely indebted to you,especially sdkl (as usual)! After a spell of painting I realized I had left one out (I assume what you didn't comment on is correct)---namely 10B:"top modern artist has briefly moved forward" -- ?S?I?T
Further, despite earlier hints I fail to see the 2 thematic names,if they are to be found by jumping over the black squares.
And now for an anagram of the moved letters!
This is threatening to ruin my Christmas!