J.S.
WHen my 2nd son was born my oldest was 9. He was excited about his new sibling but I wanted to give him a special gift that would last a lifetime. My (now ex) husband and I let him choose his new siblings middle name. Perhaps you could consider that? Let the 2 older sibs choose an appropriate middle name that means something to them...Even if Baby already has a middle name, let them pick a 2nd one. So baby has 3 names plus a last one - so what? This is a gift that literally lasts a lifetime.
When people ask my children's name I always say my 2nd son's middle name of Kyle as the one his big brother gave him...
Just a thought. :)
Warmly,
J.