Thank you for your questions! I can't speak for all adoptive parents, but I will do my best to answer them.
When I adopted my daughter, I did so because of a deep desire to be a parent. I wanted to love, raise, nuture, teach and support a child. Did I feel empty at times before becoming a mom? Of course, I did! Losing two babies to miscarriage made it even more likely that I would experience periods of emptiness. But that doesn't mean I adopted because of a need to fill my emptiness. I adopted because being a mom was important to me.
The thought of growing old and being alone never even occurred to me. I have plenty of people in my life who love me, so I'm not concerned I will be all alone.
We didn't adopt internationally, but I know many adoptive parents who have, and they do their very best to encourage their children to embrace their roots and culture. There is always loss associated with any adoption. That is something you must deal with. However, international adoption is not a bad thing. The ultimate goal is always to find a loving, stable home for a child. Sometimes that means they must leave their country of origin. I believe they can still maintain their roots to a certain degree by learning about their birth country, traveling there, eating ethnic food, connecting with birth relatives, etc.
As far as "choosing" a child, that typically isn't how adoption works. In most cases, you are either matched with a birth parent who selects you (domestic adoption) or you receive a referral from your agency (international adoption). You don't pick your kids the way you would choose a pet. You can certainly choose the type of adoption you would like to pursue (domestic, international, foster care). And, some potential adoptive parents select countries that they have an interest in or connection to, but that is usually where the choice ends. Some organizations do have databases of waiting children, but they are usually the ones who have special needs or medical issues. It is more difficult to find homes for these kids, so they use a photo listing to increase their chances of finding a good home. In my opinion, there is very little choice or control in the adoption process. You never know what is going to happen or which child will join your family.
Hope this helps!