if you are doing cheap work it might be ok but the X5 is nowhere up to indoor footage in any form. Use a tripod with slider. The seasick look is for really cheap looking videos only.
The widest and sharpest will be Olympus 12mm, next below 12mm will be Panasonic Lumix G 9mm Fisheye but I'm not sure if this effect is good for the job. Whatever, you will have to practice the "ninja walk" ...
Yes, slider seems to be a must for this kind of work. But than why bother with limitations of 12mm Oly and X5 on Osmo, and not to use any decent DSLR with suitable wide angle lens for interior shots?