I'd open it above like a 'pass-through' and bring the table out in front of it with a bench under the opening.

Could you look at separating walls between the two? What else do you want to put in the bathroom? Probably the best type of tile is a white ceramic tile to blend the floor toilet with the floor. Do users have good vision (not elderly) as if there is a problem of using the floor toilet in the night, you might need a darker tile to delineate the floor toilet

There is no average height for the table and chairs.There're height standards for all the furniture. The standard height for the table is 30" and for the chair, it is 18". The depth of the table should be atleast 36". It might be a little broad say 42" but not more. The length if the table is defined with the seats required. The chair seat size should be 16" with the back height be 30" atleast. It might be more depending upon the design of the table.

Kelly, if you would want it to appear in the center, you may have to add a mirror half way up on the left wall. Adding long barn shelves on the back side will add to the centered look. The shelves should touch the mirror for a seamless look. Back wall can be spruced up with handmade tiles. Thanks, Nitin Cornerstone Designs