You're incorrect as all of your citations have to do with total casting of powers across the army. In matched play there is a restriction on all powers other than Smite that an army can only try to cast that power once. The restriction I am talking about is not only happening in matched play but always happens in all forms of playing Warhammer 40K and has to do with how many times a single unit can attempt to cast the power. The rule that limit each caster individually to only attempt each power once is not part of the rules that distinguish matched play from open play and is part of the core rules.
Even if you should so happen to disagree with me, I highly doubt that any tournament organizer or serious player of the game would agree with your interpretation given that it is clearly spelled out in the rules for the psychic phase how this works. I would never attempt to the cast Smite multiple times with the same caster in a tournament and I expect that any attempts to do so would result in the tournament organizer telling you you could not.
Well, not that my local TO's are that serious, which is a known flaw, they still got this one right.
I think the restriction you are looking at is:
"A psyker (singular)
cannot attempt to manifest the same psychic power more than once in a turn."
The emphasis on singular is my doing.
You then accept matched play is more restricted than open play or narrative. Agreed?
In those two kind of games(open play and narrative), 2 farseers are clearly allowed to both attempt to cast doom, both only once each.
In matched play only one of those farseers would be allowed to attempt to cast doom, hence more restricted.
However smite is exempt from both restrictions in matched play in order to allow them to at least cast smite, when there are too many psykers on the table.
The other possible interpretation is that matched play is less restricted and by that allowing 2 farseers to both cast doom in matched play, because the once per psyker restriction is lifted. Here is where smite would instead be restricted to once per psyker, because it is exempt from having it's restriction lifted.
The reason I think the first interpretation is the correct one is because it's singular.
Actually the first interpretation is the correct one, and the old FAQ is why:
Q: If the Strength from Death ability is triggered, and
I choose to manifest a psychic power as if it were the
Psychic phase, can I attempt to manifest a power that
another psyker in my army has attempted to manifest
A: Yes. Note, however, that if you are playing a matched
play game, then the Psychic Focus rule still applies,
in which case your psyker cannot attempt to manifest
a psychic power that has already been attempted
by another psyker in your army this turn (with the
exception of Smite).