My understanding is that Mr. Todd views the Mitchum brothers as his mortal enemies.  So when one of their hotels burned down, he and Antony Sinclair falsified the insurance assessment to make it look like arson when it wasn't.  As a result they never received the insurance payout, which was sizeable.  Around $30 million.

Mr. C needs Cooper dead.  Mr. Todd works for Mr. C.  All previous assassination attempts having failed, he decides to convince the Mitchums that Dougie Jones is the one responsible for the insurance scam.  That way, they'll be angry at Dougie and exact retribution.  Only Dougie isn't really Dougie anymore, he's Cooper, so they'll end up killing Cooper just as Mr. C wants. 

Please let me know if I wasn't clear enough - it's not so easy to explain with Cooper now filling Dougie's shoes...

Yes that makes sense. Thank you!

Like with Ike, we know the attempt to kill Coop will fail, because that'd ruin the show to have Coop killed and Mr. C. running loose ( and a promo video showed Coop back to himself, alert mind in some scene to come later ).