The level of Oromo admixture will likely differ among the various clans, with the Dir having the highest level due to partial assimilation and a long residence in the region. They are probably followed by the Geri, and then the Jidwaaq. I very much doubt that the Ogaden, in Ethiopia, have any Oromo admixture. I would posit that the Habar Awal have more Oromo admixture than the Ogaden of Ethiopia. With the Omotic component serving as a proxy for Oromo admixture, I would estimate that none of these groups have any more than 5% of the average genome coming from the Omotic component, with there being a cline downwards from the assimilated Hawiye and Dir.
There is no evidence for any of this as we do not yet have genomic data for clans.
Somalis being a randomly mating population have created their own tight cluster in the horn. It is very easy to identify a Somali genetically. Anyone outside of that tight cluster is not an ethnic Somali as we have historically understood it. The Somalis that are likely to be the least admixed are those from the Hawd, of any clan, excluding the Sheekhaal.