First, I think this is an excellent initiative and its good that you have such co-operation from the ER.

my advice is that as a first step you should think what kind of MG patients would be coming to the ER and why.
I believe you would have a mixed population of not yet diagnosed, recently diagnosed and "highly experienced" MG patients, and each would probably require a somewhat different approach.

I would also check which neurologists and respiratory physicians have admitting permissions in your hospital and try to work with them.

Ideally, I would try to contact MG patients, living in your area, who have been in this ER and try to get from them first-hand what was good and what they think should be improved.

I would then prepare educational material for the staff, and for the patients. I would try and get one or two people from the staff highly involved so that they can educate others.

I can't specifically comment on guidelines I have not seen, but as a rule guidelines on their own are not enough and create what I call- "flow-chart physicians" , which is one of the flaws of modern medicine.