What are the functions of these parts of the brain (MRI)?

Three spots in the brain do not automatically mean three different symptoms. Even if those spots are abnormal, they do not necessary cause any damage.

A doctor in the "2. MRI report" says there are:

...few bilateral parietal subcortical tiny white matter foci...warrant further evaluation to exclude possibility of early onset MS.

So, there are 3 tiny spots in the white matter of the parietal lobes of the brain.

Parietal Lobes (Brainmadesimple.com):

Function: Processes sensory information that had to do with taste, temperature, and touch

Brain Lesions (MedicineNet):

Parietal lobes are where sensation is processed and interpreted. Aside from touch, pressure and pain, there is also the concept of spatial cognition, where the brain recognizes where the body is in relationship to the area around it.

What is the function of the parietal lobe? (Reference.com):

Patients with damage to the parietal lobe can suffer from language or memory loss and might also be unable to hold a gaze. Thus, the parietal lobe helps people recall words when speaking.

The visual processing within the parietal lobe facilitates writing and mathematical calculations. The parietal lobe is also responsible for perception and language processing.

Memory Dysfunction in Multiple Sclerosis...(American Journal of Neuroradiology):

Lesions of the deep white matter in the left parietal lobe have been found to be associated with impaired performance on the paired associates test, a test of learning and memory.

I'm not saying you should or will suffer from any of these symptoms. A neurologist, who can perform an exact neurological examination might detect some signs you are not aware of.