Bushiri, 22, made 15 appearances following his January arrival to trigger the option of a permanent move.
His signing comes after 20-year-old striker Momodou Bojang joined on loan from Gambian club Rainbow FC.
Gambia Under-20 cap Bojang spent last season with Famalicao's Under-23 side in Portugal, scoring six goals.
New Hibs manager Lee Johnson says centre-back Bushiri has "a lot of attributes" to be successful.
"He has obvious strengths and it'll be interesting to see how quickly he can adapt to a new playing style," Johnson added.