I think you'd need descent from the founder of the bloodline or from someone very close to them. I forget the exact connection Phelan had to the Ward founder.
While the Steiner bloodname does descend from a member of House Steiner I don't know that it was that close to the mainline.
Phelan was the son of Salome Ward, a direct descendant of Michael Ward, founder of the Ward Bloodname.
Checked the reference and the founder of the bloodname was Michael's son Jal, but it was claimed that Jal went with the Exodus because his father couldn't.
The only Paul Steiner I'm aware of was the grandfather of Claudius the Cruel. He was LCAF commander under his siblings Robert and Jennifer. While Sarna implies that Paul Steiner fought alongside Kerensky neither of the two sourcebooks referenced back that up so that could be an error. It would be entirely possible that it was only Kailen who joined the SLDF, the Exodus and eventually the Clans.
And relevantly, although Paul was the youngest sibling, Victor is a descendant. Of course, as a non-SLDF member, ancestry from him may not carry much weight with the Clans.