Hi there,
The ballet company I work for is larger than Milwaukee Ballet, so making a direct comparison of some conditions and terms would be unfair, but here are some basic answers to your questions, based on my situation.
I am a member of Canadian Actors' Equity Association, as are all the dancers in my company. CAEA is officially a professional association, not a union (except in the case of it's members in Alberta Ballet - long story), although it engages in collective bargaining.
I work under an annual renewable contract, the terms of which are set out in the collective agreement between my company (the Engager), and CAEA. Terms include salary, work schedule, additional service billing (overtime), responsibilities, etc. In Canada, most mid- to large-sized ballet companies have agreements with CAEA, and dancers who are members. The collective agreements that CAEA has with these companies are publicly available. I would recommend you have a look at a couple of them, as they would probably give you a good idea of not only the scope of defined terms, but also what some of the terms imply as far as working conditions go. You can find the agreements at
http://www.caea.com/EquityWeb/EquityLibrary/Agreements/Dance/DanceLibrary.aspx. I think the agreements you should look at are the ones for Alberta Ballet and the Royal Winnipeg Ballet, as they are closer to the size of your company.
I have two basic work schedules that I can generalize about: the rehearsal period, and production/performances. When the company is in rehearsal, I tend to work an 8 or 9 hour day, sometimes adding evening or weekend hours depending on whether I need to do some additional work at home - lets say about 48 to 50 hours a week. Our rehearsal week is generally a 5-day week, Monday to Friday. Once we are in a production/performance period (either at home or on tour), my work week can be 6 or 7 days a week for up to 4 weeks at a time, and work days can be 10 to 15 hours long.
Our stage management team consists of two stage managers working full-time for the company, and we hire an ASM for a total of 15 weeks per year, dividing the weeks up based on repertoire or schedules that are most demanding (always for Nutcracker, then wherever else makes sense). The company hires one more stage manager to support a small group of dancers that do a series of educational performances. Company management responsibilities are handled by a couple of staff (strangely, we don't really have a single person with that job title), and as a stage manager I have virtually nothing to do with company management-related responsibilities. When I have worked for smaller companies and independent dance artists, this is definitely one area where the lines between stage manager and company manager blur.
My pay is determined by the terms of the collective agreement I work under, which is a minimum scale agreement. There is a grid that indexes positions with number of years in that position, and results in a minimum fee. Anyone working under the agreement is welcome to negotiate above scale. All dancers and stage managers with my company are paid a weekly salary. Depending on how long an individual artist has worked for my company, some annual contracts are 46 or more weeks a year, and some are full-time, or 52 week contracts.
According to the terms of CAEA's collective agreement, all artists (dancers and stage mangers) are entitled to bill the Engager for 'additional services' (overtime) when certain conditions are met (rehearsal hours exceeding maximum allowable, overnight rest infringement, etc.). The terms in the agreement are more specific for dancers than for stage managers, and historically, dancers are more likely to bill for additional services.
I hope this is a bit of help. Reading through some of the collective agreements I mentioned above might be the best framework for you to adapt to your needs. I don't know how accessible AGMA agreements are, but here's an expired one for San Francisco Ballet, which includes their stage management staffing:
http://www.musicalartists.org/agreements/sanfranciscoballet.2010-2013.pdf.
Are any of the dancers in your company members of Equity or AGMA? I definitely think your work hours should be one of the first things you define with your engager; how many they expect of you, and how you will be compensated beyond that. I would recommend that if you don't already, start keeping a daily log of your work hours, so that you will have a clear record to refer to. Working without some kind of contract of letter of engagement is a recipe for acrimony and recrimination.