Rename: Strip text at start and end of filename

I'm looking for a script that does the following renaming action.

STEP #1
Strip all characters preceding a certain string. Example: 05

STEP#2
Remove all characters after character 6

STEP#3
Rename all E's to x (not case sensitive)

STEP#4
If the first character of the filename is a 0 (zero) then remove it.

Is the "certain string" in step 1 the same every time? And is it always in the same position or can it change?

In step 2, is character 6 counted based on the original name or after it has gone through step 1?

For clarity can you show some examples of filenames before and after the desired rename?

The "certain string" is in different positions.
The "certain string" varies but has only a few 'values'
01
02
....
12

0=zero

All steps assume the filename after it's stripped by the previous step.

Examples.

This.prefixes.year.and.clip.08e17.of my vacation in Italy.mp4
Result should be 8x17.mp4

This clip was filmed in 1999(France) --- 18e17.mp4
Result should be 18x17.mp4

In other words:

Only the bold text and extension should remain.
If the bold text contains any letter not being an x then replace that letter with an x

Try this:

Mode: Regular Expressions
Old name: ([1-9][0-9]?)[a-z]([0-9]+)
New name: \1x\2