I'm not certain of the identity of that other one,
I wouldn't rule out Hoya as a possibility,
but several other possibilities occurred to me when I saw it,
not Periwinkle though, I think.
You could go ahead and repot it if you feel it needs it.
Just use a good, general purpose houseplant medium.
When repotting any houseplant,
I usually rinse away as much of the old potting soil
as will wash away easily when gently sprayed with a garden hose.
That gives me a chance to have a look at the condition of the roots.
If there are any clearly unhealthy looking roots,
I trim them away with clean clippers.
If I put a plant
back into the same pot it came out of,
I wash the pot well first, using a mild bleach/water solution.
Hope that helps.