My question is whether constructions similar to the following English one, which is drawn from Jespersen (1909-1949, vol. V: 138), can exist in Latin, i.e., constructions where (i) the subject is formed by a plural noun plus an obligatory/"dominant" predicative participle but (ii) the verb is in singular form. Notice that it is not the two old men themselves that are funny, but the fact that they are dealing with an inappropriate theme. Hence singular agreement (seems) is justified.
[Two old men dealing with such a young theme] seems funny to me.
Next consider the two following examples of so-called "dominant" participle and gerundive constructions, taken from Sallust and Livy, respectively:
(Dixit) se missum a M. Crasso qui Catilinae nuntiaret ne eum Lentulus et Cethegus aliique ex coniuratione deprehensi terrerent. (Sall. Cat. 48,4)
&
Bello Graeci persequendi Publilio evenerunt. (Livy 8, 22, 9)
Although the subject is plural, I was wondering whether the verb could also be singular in these two examples (i.e., terreret and evenit). My intuition is that it couldn’t but perhaps I’m wrong (NB: as for the first Latin example above, it is not a plurality of individuals but the event/fact that these individuals were arrested what would frighten Catilina. Furthermore, note that Lentulus and Cethegus were accomplices/friends of Catilina: so it is clear that what could frighten Catilina was not them (as individuals), of course, but their arrest (i.e., a situation). As for the second example with a dominant gerundive, again it is not the Greeks but rather their having to be persecuted through a war (considered as as a future event to be accomplished, e.g., as a duty) what fell/"came" to the consul Publilius). Anyway, I would like to know whether examples like the English one above could also exist in Classical Latin.
Rethinking on this question, an invented Latin example similar to the attested English one above with the verb "seems" could be the following one:
Cum legati occisi aliis pessimum, aliis pulcherrimum facinus videretur.
(cf. the attested example in Tacitus, who, as is well-known, uses many dominant participle constructions: Cum occisus dictator Caesar aliis pessimum, aliis pulcherrimum facinus videretur (Tac. Ann. 1.8). Note that, semantically speaking, the nominal predicate facinus ‘crime’ requires its subject to be a situation ('the murder of Caesar'), rather than an individual ('dictator Caesar')).
My intuition is that viderentur (3rd plural) would be the expected form in my invented example above but I don't know if videretur (3rd singular) would also be possible (perhaps, in this case, due to a possible attraction by facinus).
For a similar construction in Romance, cf. the Italian pseudorelative construction, drawn from Casalicchio (2016): I bambini che giocano agli anziani mi {fanno/fa} ridere; lit. 'The children that play at the elder {make/makes} me laugh'. According to this Italian linguist, both verbal forms fanno 'make.3pl' and fa 'make.3sg" are possible here.