I don't know enough about mead, cider or lemonade (as in the required cell count) but once you know that Mr Malty can show you how to make the numbers you need. Also Jamil's book has an excellent resource for stepped starters (table) also correlating numbers to size of starters. A guy made a video about how to use the table that is really helpful to understand numbers of yeast and how they multiply here is the link, note the table does not take into account stir plates.
As far as making three steps starters I will explain my process in which I use a pressure cooker (poor man's autoclave) and stir plate. If you are going to play with yeast it is the best $30 you can spend. Craigslist or Ebay a pressure cooker and you can "Can" your starters ensuring sterility which is much better than sanitized.
I usually have pre-pressure cooked (canned) my wort for starter so it is ready to go. So I will sterilize my starter vessel (if it fits in my pressure cooker) or I will boil water in it with the stir bar and foil lid in place. This way I can use only a small amount of water and it cools really quickly and then I add the canned wort cooling the whole lot to pitching temps, then I can pitch my yeast. If it is on a stir plate (which you get much larger growth rates on you don't have to worry about for a day or so. Everyone has a different opinion on how long to leave it but enough to say that you should see if foam up and form a krausen (even on a stir plate). If you don't have a stir plate then use O2 or shake it as often as you can to increase growth. Once the starter is done crash cool it for 24-48hrs. This causing the yeast to settle out, then you can decant the spent wort on top of the yeast and add more canned wort (or boiled and cooled if you don't can your starter wort) If you use a larger container to begin with you can do this all in the one container, 1000ml 3000ml maybe even 5000ml. Once you have enough yeast you can store it in a sterilized jar. This is where the pressure cooker comes in handy again. You take some clean water in a jar big enough to hold the yeast +50% more pressure cook it so it is sterile, take the yeast and crash cool and decant the spent wort as before then swirl and poor into the sterile water. this will allow the yeast to keep for a few weeks however your viability is dropping off every day.