Solutions

Question 1:

For 1-22: ClassDef may be replaced by its superclass: Definition

1 Program
2 to			(to-stop works too)
3 ClassDef
4 DoParse
5 DontParse         3,4,5 in any order
6 ClassDef		
7 ClassDef
8 DontParse
9 DoParse
10 Program
11 to			(to-stop works too)
12 BeginVisitors
13 EndVisitors
14 ClassDef         12,13,14 in any order
15 BeginVisitors
16 EndVisitors
17 ClassDef
18 ClassDef
19 Program
20 Program
21 ClassGraph
22 ClassGraphEntry_DList
23 ClassDef
24 Nothing
25 DontParse
26 ClassDef
27 BeginVisitor

Question 2:

see answers-raw/quest2 subdirectory 

Question 3:

1 (
2 )
3 "="
4 ":"
5 NOTHING
6 CHOICE
7 PartKeyword
8 ReadOnlyPart
9 read-only
10 PrintCommand
11 PrintUnindent
12 -
13 List
14 S { "|" S }.


Question 4:

You cannot traverse to terminal classes (Ident, String, ... ) so you
have to use part names to access these parts. Otherwise, yes, you could
eliminate part names at the cost of introducing extra classes which
basically encode the part name as a class name (to deal with the 
situation in which a class has several parts of the same type).