There are J1 Reer Gibil Cad. I had about two of their samples emailed to me like a decade ago, in fact.
Arab settlement is perhaps way overstated and, ironically, it's more Somalis who settled in Arabia when you look at accounts of places like Yemen during the Early Modern era where Somalis had a quarter of their own in Mukha by 1762 and were so integral to Aden's 19th century economy that when they threatened to all leave in unison the British exclaimed that Aden would be done overnight if they did so.
But even so, merchant Arabs definitely existed and were noticeable on our end. You mentioned Indians and if you look at a 19th century census of Xamar by the Italians the actual Arab and Indian population were pretty much equal in number. Gibil Cads don't draw from just Indians, don't know where you got that sense.
They tend to look ~20% Indian, 30-40% Somali, 5-10% Bantu and the rest is a diverse smattering of what seems MENA; Arab, Iranian, Central Asian like Uzbek and so on. The Banaadir seemed to attract people from all over the Muslim world in its heyday.