The above three substitutions still allow you to improvise over the blues using the Minor pentatonic scale or the Blues scale.
But be aware of these chord substitutions when they are used in a song.
Knowing, hearing and reacting to all chord changes are the hall mark of a good improviser.
The Embellished Blues format dramatically affects the improvisation when using Mixolydian modes or other individual scales for each chord.
The scales used for an Embellished Blues in C for example are :