With no explanation, label text_A→text_B with either "DON'T KNOW", "NO" or "YES".
text_A: Francesco Rognoni was another composer who specified the trombone in a set of divisions (variations) on the well-known song "Suzanne ung jour" (London Pro Musica, REP15). Rognoni was a master violin and gamba player whose treatise "Selva di Varie passaggi secondo l'uso moderno" (Milan 1620 and facsimile reprint by Arnaldo Forni Editore 2001) details improvisation of diminutions and Suzanne is given as one example. Although most diminutions are written for organ, string instruments or cornett, Suzanne is "per violone over Trombone alla bastarda". With virtuosic semiquaver passages across the range of the instrument, it reflects Praetorius' comments about the large range of the tenor and bass trombones, and good players of the Quartposaune (bass trombone in F) could play fast runs and leaps like a viola bastarda or cornetto. The illegitimate term "bastarda" describes a technique that made variations on all the different voices of a part song, rather than just the melody or the bass: "considered legitimate because it was not polyphonic".
text_B: Could a person singing a solo be considered legitimate bastarda?
YES.