Who in the UK has a bigger profile in rugby than Owen Farrell?? Outside of the M62 corridor nobody could name any NRL player irrespective of his standing in Australia.
If I'd a choice of any NRL player or Farrell I'd take Farrell in a heartbeat. He is class and a pretty tough guy to boot and I'd love to see him in the 13 shirt at Wigan. He is a quality player in Union but I think that his style of play and his aggressiveness make him an ideal player for RL. Commercially and technically Farrell would in my opinion be a true superstar in RL.
Tedesco is pretty handy but in terms of attracting new spectators I'm pretty confident that he'd get nowhere near what Farrell would do.

I wouldn't pick a player just cos of their profile. I'd pick him on ability if I could literally pick anyone in world rugby. If even though I do believe Owen could be a success in league, if I was picking right this moment, I'd pick a RL player to play RL, I can't honestly say how good Owen would be at league.

Neither could I but you could say the same about any player from the NRL. For every success story of an Aussie or Kiwi there are tenfold who just add zero impact to the sport when they play over here.
Farrell would be a guaranteed commercial success and I honestly believe he would also be a superstar player. I'm not a great Union fan but I do enjoy watching Farrell on how he organises the game with great technical skills and generally with great composure.

I wouldn't be signing a player for commercial success. I'd be signing who I believe to the best RL player in the world, simple really. Will it work out? Who knows, hypotheticals, could ask the same question of any new signing.

If you would only sign RL players then historically we never have signed Boston, Inga, Botica, Flower etc. Widnes would never have signed Offiah.

Doesn't mean right now I should now pick a rugby union player if I had one pick, just because there's been great converts in the past.