They were both Seekers. He saw a picture of a Hogwarts Quidditch team with Regulus sitting in the middle of the front row where the Seeker sits.
2.On three ocassions former professors can be presumed to have "visited" the trio while they are in "exhile" - which professors and which ocassions would these be?
Phineas Nigellus Black - visited the trio in the woods where the Quidditch World Cup was held (talked about Gryffindor's sword)
3. How do Ron and Harry get into the Ministry?
They each drank some polyjuice potion and took on the appearence of ministry employees. Hermione become Mafalda Hopkirk. Rom becomes Reg Cattermole. Harry becomes Runcorn. Then they flushed themselves down a toilet to enter the Ministry.
The blond-haired boy was Gellert Grindelwald - he stole the Elder Wand from Gregorovitch the Bulgarian wandmaker.
7. Bathilda Bagshot does not speak in front of Hermione and Ron because....
It was Nagini inhabiting Bathilda's body. Harry would be able to understand the Parseltongue (the language of snakes) but Hermione would not. Ron was not even there as he had already left.
Dobby the House Elf
Tom Riddle's Diary
a. Harry destroyed Tom Riddle's diary in 'Chamber of Secrets' with a basilisk fang.
Tom Riddle's grandfather inherited the stone of resurrection. Harry's father inherited the invisibility cloak. What does this imply about Tom Riddle and Harry Potter?
The Resurrection Stone was first owned by Cadmus Peverell and the Invisibility Cloak was first owned by Ignotus Peverell. Since the two items were passed down thru the families for generations, it can be safely implied that Tom Riddle and Harry Potter are distant relatives.