That seems extremely unlikely. Attacks on solicitors and their interests only known in the most serious organised crime / paramilitary cases e.g. Finucane.
But it raises a broader point that all the candidate motives appear strange. The most likely - something connected with personal relationships - are still pretty odd. You can understand a man being concerned about an affair becoming public knowledge and damaging his marriage. But to consider murder (probably with accomplices) to protect that is extraordinary. Similarly, whilst jealousy can trigger wild bursts of emotion, those emotions don't fit with a well-planned and executed operation, probably involving a few people.
Could a relationship have got mixed up with other interests, including financial? Blackmail is one variant of that - blackmailers do get murdered, especially within criminal circles. But if anything Claudia seemed to excited by / supportive of those men she met with shady(ish) sources of money. Her personality doesn't seem compatible with the ruthlessness needed for blackmail. And she didn't seem particularly focused on making a lot of money.