No uniform realisation is possible: if cells would become uniform variants (cubes), then the vertex figure should become a tridpy, which in turn is not orbiform. But uniform realisations always require orbiform vertex figures.

Incidence matrix according to Dynkin symbol

s4x2s4x

demi( . . . . ) | 32 |  1  1  1  1  1 | 1 1 1  2 1  2 1 | 1 1 1 1 2
----------------+----+----------------+-----------------+----------
demi( . x . . ) |  2 | 16  *  *  *  * | 1 1 0  1 0  0 1 | 1 1 0 1 1  x
demi( . . . x ) |  2 |  * 16  *  *  * | 1 0 1  0 1  1 0 | 0 1 1 1 1  x
      s 2 s .   |  2 |  *  * 16  *  * | 0 0 0  2 0  2 0 | 1 0 1 0 2  q
sefa( s4x . . ) |  2 |  *  *  * 16  * | 0 1 0  1 1  0 0 | 1 1 0 0 1  w
sefa( . . s4x ) |  2 |  *  *  *  * 16 | 0 0 1  0 0  1 1 | 0 0 1 1 1  w
----------------+----+----------------+-----------------+----------
demi( . x . x ) |  4 |  2  2  0  0  0 | 8 * *  * *  * * | 0 1 0 1 0  xxxx
      s4x . .   |  4 |  2  0  0  2  0 | * 8 *  * *  * * | 1 1 0 0 0  xwxw
      . . s4x   |  4 |  0  2  0  0  2 | * * 8  * *  * * | 0 0 1 1 0  xwxw
sefa( s4x2s . ) |  4 |  1  0  2  1  0 | * * * 16 *  * * | 1 0 0 0 1  xqwq
sefa( s4x 2 x ) |  4 |  0  2  0  2  0 | * * *  * 8  * * | 0 1 0 0 1  xwxw
sefa( s 2 s4x ) |  4 |  0  1  2  0  1 | * * *  * * 16 * | 0 0 1 0 1  xqwq
sefa( . x2s4x ) |  4 |  2  0  0  0  2 | * * *  * *  * 8 | 0 0 0 1 1  xwxw
----------------+----+----------------+-----------------+----------
      s4x2s .   ♦  8 |  4  0  4  4  0 | 0 2 0  4 0  0 0 | 4 * * * *
      s4x 2 x   ♦  8 |  4  4  0  4  0 | 2 2 0  0 2  0 0 | * 4 * * *
      s 2 s4x   ♦  8 |  0  4  4  0  4 | 0 0 2  0 0  4 0 | * * 4 * *
      . x2s4x   ♦  8 |  4  4  0  0  4 | 2 0 2  0 0  0 2 | * * * 4 *
sefa( s4x2s4x ) ♦  8 |  2  2  4  2  2 | 0 0 0  2 1  2 1 | * * * * 8

or
demi( . . . . )   | 32 |  2  1  2 | 1  2  4  2 | 2 2 2
------------------+----+----------+------------+------
demi( . x . . ) & |  2 | 32  *  * | 1  1  1  1 | 1 2 1  x
      s 2 s .     |  2 |  * 16  * | 0  0  4  0 | 2 0 2  q
sefa( s4x . . ) & |  2 |  *  * 32 | 0  1  1  1 | 1 1 1  w
------------------+----+----------+------------+------
demi( . x . x )   |  4 |  4  0  0 | 8  *  *  * | 0 2 0  xxxx
      s4x . .   & |  4 |  2  0  2 | * 16  *  * | 1 1 0  xwxw
sefa( s4x2s . ) & |  4 |  1  2  1 | *  * 32  * | 1 0 1  xqwq
sefa( s4x 2 x ) & |  4 |  2  0  2 | *  *  * 16 | 0 1 1  xwxw
------------------+----+----------+------------+------
      s4x2s .   & ♦  8 |  4  4  4 | 0  2  4  0 | 8 * *
      s4x 2 x   & ♦  8 |  8  0  4 | 2  2  0  2 | * 8 *
sefa( s4x2s4x )   ♦  8 |  4  4  4 | 0  0  4  2 | * * 8

or
32 |  2  1  2 | 1  4  4 |  4 2
---+----------+---------+-----
 2 | 32  *  * | 1  2  1 |  2 2  x
 2 |  * 16  * | 0  0  4 |  4 0  q
 2 |  *  * 32 | 0  2  1 |  2 1  w
---+----------+---------+-----
 4 |  4  0  0 | 8  *  * |  0 2  xxxx
 4 |  2  0  2 | * 32  * |  1 1  xwxw
 4 |  1  2  1 | *  * 32 |  2 0  xqwq
---+----------+---------+-----
 8 |  4  4  4 | 0  2  4 | 16 *  s4x2s
 8 |  8  0  4 | 2  4  0 |  * 8  s4x2x

starting figure: x4x2x4x