Because I could not find the answer to these questions easily via Google, I am sharing my answers.
1. Can you use a PicoBoard and a WeDo motor at the same time in Scratch? YES. I have two USB ports on my laptop, and although for some reason I had to plug and unplug and refresh Scratch a few times, in the end I was able to use the PicoBoard and WeDo together (using PicoBoard sensors to start the WeDo motor). I didn’t really do anything fun with it beyond get it working, though.
2. How do you get the slider on the PicoBoard to make a sprite go all the way across the screen? The slider sensor uses values from 1 to 100, which means it starts in the middle of the screen and goes to the right a bit when you set x to slider sensor value. In the end, I came up with this (set x to (slider sensor value – 50) * 5) , which isn’t exact because I did some rounding (i.e., the paddle goes off the screen a little on both sides), but works for what I wanted to do:
I ended up making a simple pong game and then a simple catch-the-ball game using the slider, learning a bit along the way about cloning sprites and scoring:
All in all, a productive and enjoyable evening!