Are there any risks of having widely spaced and small teeth?

No risks. Having spacing between teeth actually makes it easier to keep them clean an may actually reduce your chances of getting tooth decay. .
Depends. There may be aesthetic (on your part) concerns. Widely spaced may be easier for you to clean (so long as you maintain well) ; thereby have less chance of decay starting between the teeth. Small teeth may only be a problem if you clench or grind your teeth as you will wear them down. Talk to your dentist, who has actually seen your teeth and spacing to see what their thoughts may be.
Probably not. As long as occlusion is stable, you're probably OK. If the esthetics bother you, or if there are functional problems, best solution would probably be for specialist Orthodontist to reposition teeth to create the best platform on which to accomplish Restorative treatment. See an Orthodontic Specialist, initial exam usually free.