Thank you! I just read in Techniques In Winemaking (Daniel Pambianchi) that you can use grape juice, must etc too instead of water. Make sense as they are loaded with sugar.You can use any container you want. Just cover it with a towel or something similar. FWK recommends a wine bottle, and it makes sense as most of us have a bunch lying around. I have numerous funnels that fit wine bottles (including a large one!) and put the dry ingredients in first, then the water.
Last spring I wrote a post that describes making a starter in greater detail. I updated it this morning with advice for conical fermenters.
https://wine.bkfazekas.com/how-to-make-a-yeast-starter/