Now, the question is: can I make Vigor, Mass Lesser persistent?
The conflicting part is: Vigor, Mass Lesser has duration 10 rounds + 1 round/level (max 25 rounds). So it has a maximum duration and hence cannot be persisted, according to my DM, but there are a tons of builds on the internet, where Mass Lesser Vigor is considered something that can be made persistent.
The key argument in those threads is: persistent spell doesn't extend the duration of spell to 24 hours, but more like replaces it, but the wording of feat clearly states...
Spells with a fixed or personal range can have their duration increased to 24 hours. Spells of instantaneous duration cannot be affected by this feat, nor can spells whose effects are discharged.
And yet, it still does not say that spells that have max duration amount cannot be persisted to 24 hours, kind of confusing.