Under a family-first order, should St de Mesnil Jean read given 'Jean', as Dr. de Mesnil Jean does? #828

Under a family-first order with no comma, P1's fold takes the leading particle run plus one name unit as the family and lays out the rest by the order (#395). A plain title in front changes nothing, because P1 says a title does not move the opening position. A word that is both a title and a particle (St, Freiherr) is P4's exception. Behind one, P1's fold never runs, so the one-unit stop doesn't apply and the family takes every word:

The given-name titles aren't the cause: Dr. reads as Sir does. Neither rule says which wins, P1's stop or P4's exception. Under the default order all of these read the whole rest as family, so only the family-first orders differ.

Proposal, in rule shape

When: a title-particle opens the name, followed by a particle run and more than one name unit, under a family-first order.

Then, one of:

• (A) the declared order bounds the run as it does behind Dr.: family 'de Mesnil', given 'Jean'.
• (B) as today, with a Precedence bullet in P1 or P4 saying the exception wins.

Because: the family-first order is the caller's declaration of where the given name stands, and P1 lets it bound the run. P4's exception is about whether the head word is a title, not how far the particle run reaches.

Open questions

1. Under (A), Freiherr von Berg Jean reads given 'Jean'. Does that interact with Should Otto Graf Lambsdorff read family Graf Lambsdorff, as Manfred Freiherr von Richthofen reads family Freiherr von Richthofen? #709, where the rank may belong to the surname?
2. Without a comma, a family-first family is one unit after the particles, so multiple surnames (Garcia Lopez Juan → family 'Garcia') aren't handled under any title. Is that worth its own issue?