Question for adults with spina bifida. Can they have loss of motor function or inability for orgasm if low?

Yes. Spina bifida oculta usually has no neurological deficit, norma, . 10% of population. Open & close spinal bifida usually will have motor and sensory deficit like para/quadriplegia, decrease sensation/orgasm, respiratory problem (due to chiari malformation . Intelligence usually not affected.
Possible both absent. Neurologic loss in adults with spina bifida/myelomeningocele varies greatly depending on degree & level of spinal cord involvement. Subjects with low spinal cord lesions can usually walk, but may require lower limb orthoses. Genital area may well be devoid of any sensation, again depending upon level of of cord involvement thus some subjects may have minimal motor loss yet are unable to orgasm.