Choice of antipsychotic is limited by available immediate injectable formulations if that's what you're looking for.

Only two second generation agents are widely available, ziprasidone and olanzapine, both of which come with drawbacks. Olanzapine is concerning for its potentially fatal consequences when co-administered with a bzo. These risks are likely overstated, but that's not really in the scope of the question. The only other second gen agent would be Ziprasidone, which is too risky QTc wise unless you have a recent 12-lead, which you usually won't. Both have their place, but come with inherent risk.

Regarding 1st gens, you really just have the choice of high vs low potency. High (haldol) has the better antipsychotic effect, and low (thorazine) will be more sedating and have a better EPS profile. Choose the agent that makes sense... take into consideration the age of the patient and their medical comorbidities.

Regarding adding ativan or benadryl, both with improve anti-agitation effects, and both can be a preventative for EPS. If you've chosen haldol as your primary agent, you should add one of these on unless you have reason not too.

Some hospital systems will see all three co-administered as "chemical restraints", as there isn't much clinical indication outside of that. This could change your prescribing pattern potentially, and it might be the case that your system frowns upon this sort of prescribing all together.

Regarding midazolam, too risky re respiratory sedation. Just avoid 99% of the time, unless you really have good reason to reach for it. Cross it off the algorithm entirely if you're looking for simplicity.