A maze of placed faces

Question

Twenty-nine images of famous people have been specifically selected and carefully placed so as to form a maze (below). However, two of the images - both of US Presidents - have been redacted (marked 'A' and 'B').

To navigate the maze, you must move vertically or horizontally from one image to the next, without revisiting any image. One of the four spaces marked 'START?' is the correct place to begin - you must deduce which of these it is - and the target space is that marked 'END'.

TASK: Deduce the identities of the US Presidents who should appear in the cells marked 'A' and 'B'. Plot the path taken to navigate the maze from the correct 'START?' space to the 'END' in the only way which makes sense of every carefully placed photograph.

Hint:

What connects the four potential starting squares? Where can you go from there?

_{Image credits: All images courtesy of Wikipedia pages.}

Answer 1

The two missing presidents are:

(A) George Washington and (B) Richard Nixon.

As Victor has found out ...

... the initial letters of the people in the grid are important. The letter pairs can be visited in order to form a single word. (All tiles are visited, so msh210's comment to the question is useful, but it's also easy to see why the possible starting squares could not be chosen differently.)

We get:

        GY---LL   IO---IL---YS
         |    |    |         |
        YN   GO   GO---GO   NT
         |    |         |    |
        *A   GE---RY   GO   LA
         |         |    |    |
        LL---PW   CH   CH   LL
              |    |    |    |
        FA---IR   WY    O   WL
         |         |         |
        AN---LL   *B---DR---OB
              |
              ^

Or ...

... Llanfair­pwllgwyngyll­gogery­chwyrn­drobwll­llan­tysilio­gogo­goch, the lengthened name of a village on Anglesey, Wales, designed to be the longest place name. Perhaps you've seen a photograph of the rather long sign at the village's railway station.

The letter pairs GW and RN are needed to complete the name. Oh, and the title, "A maze of placed faces" is a hint that we are looking for a place name.

Special thanks ...

... to Jerry Dean who went through the trouble of identifying all the people. That was a great help.

Answer 2

Possible first steps in solving it

This is a partial answer, likely somewhere between 5% to 30% complete. But since nobody answered this yet, it might be a small breakthrough.

First, I just copied this from a comment to a chat link (thanks for Jerry Dean) and the OP confirmed that they are all correct:

1. 

Ok, are those random names?

No.

Because:

2. The possible starting squares are Leona Lewis, Lennox Lewis, Lucy Liu and Lindsay Lohan. They all have the initials LL.

3. Gilbert O'Sullivan, Gary Oldman, Georgio O'Keeffe and George Osbourne. All of them have the initials GO.

4. Also there are a lot of people with G, L, W, Y and O as initials. This is improbable if the 27 people with known names were chosen at random or if their actual names didn't matter and they were chosen only by some other criteria.

So:

5. If this phenomenon is not a red herring intended to mislead people, this should be some sort of word puzzle.

Also, considering this comment form the OP:

@msh210 Well, I haven't actually explicitly said that every space must be visited (just that you need to make sense of the selections...) - but if you think they do need to be then I'd hope any answer would justify why :)

This means that:

6. Not every square must be necessarily visited.

Hence:

7. Some of the names might be randomly picked after all, and those would possibly be just red herrings. However, unvisited squares might be useful somehow, so I'm not sure.

Also, connecting the names, I produced this:

8. 
   Red connections are people who share both initials.
   Blue connections share only one initial.

Based on that, A should be one of:

George Washington, Abraham Lincoln, Ulysses Grant, James Garfield, Grover Cleveland, Dwight Eisenhower, Lyndon Johnson, Richard Nixon, Gerald Ford, George H. W. Bush, George W. Bush

And B should be one of:

George Washington, William Harrison, Rutherford Hayes, Abraham Lincoln, William McKinley, Theodore Roosevelt, William Taft, Woodrow Wilson, Warren Harding, Franklin Roosevelt, Dwight Eisenhower, Lyndon Johnson, Richard Nixon, Ronald Reagan, George H. W. Bush, George W. Bush, Donald Trump

Now, I got stuck.