When I have joint executors come in I let them know that I will charge them extra unless they agree to renounce down to a single executor.
I've never had a situation where it was 'easier' with multiple and many where it was far far worse.
My suggestion is to pick your least favourite child for the role... its certainly not a reward.
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"Teach a man to reason, and he'll think for a lifetime"
~P^2
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