[teruakohatu]

I think the OP means that E and Ǝ would be equivalent.

[maf8987678]

This actually works fine with latin letters. Think of for example advertising or graffiti where this trick is used sometimes to gain attention.

[OJFord]

Not all of them, depending on font (and case) - bdpq, sz.

[thaumasiotes]

It works fine with all of them. It's true that some letters are mirrored forms of other letters, but that doesn't leave any ambiguity - the form of the letter is oriented to the direction of reading, so "b" is a B when you're reading left-to-right and it's a D when you're reading right-to-left.