Very exciting!
Max had an "only child" personality, but adding a second worked out great for us. Teddy was 8 months old when we brought him home.
Cons: short-term adjustment minor issues between the boys. You may luck out and skip that all together.
It's harder to wrangle 2 Yorkies than 1 when going places. Twice as much grooming, vet bills.
Pros: Twice as much love! Twice the fun!
My boys do not self-entertain, so adding a second did not mean they kept each other busy. But they do love the company of one another.
Best wishes in making your decision!