That's cool and all but they are related to South Cushites and Maasai moreso than Eastern Cushites. From what I have gathered.
Former Burundian president was once exiled in Somalia when it was peaceful in the '80s. People who met him state he conveyed their ancestral roots to Somalis. People who traveled to Rwanda and Burundi also conveyed the same claims.
I once visited Uganda and found a Somali guy who was married to a Tutsi woman. That woman was tall and very strong and her Somali husband was short and thin. People used to say when she and her husband fight, she used to pick him up and throw him to the ground, and then used to go on the top of him.

Yuweri Musaveni, the current President of Uganda, who also has a Tutsi background, used to claim of having ancestral Somali background. That is how people who met him when he seized power conveyed. Somalis in Uganda were once treated like citizens.
So while DNA may tell a different story, just like the Somalis claiming Arabian roots or Amhara claiming King Solomon (Prophet Suleiman (peace be upon him)) ancestry have a rude awakening when the haplogroup tests were carried out, the older Tutsi claiming Somali ancestry has been consistent.