I have 2 questions regarding the following:

- How do I get the grace note to correctly indicate a hammer-on to the G# (no text on the hammer-on slur please)?
- How do I get Dorico to play back this and similar hammer-on grace notes so that the chord is first struck (on the beat) and then the hammer-on follows immediatly as is the convention in electric guitar notation?
You’ll need to position the slur manually in Engrave mode, because Dorico won’t position slurs to specific noteheads: it positions the slur either on the stem side or on the notehead side, but it doesn’t “know” that you want the slur to be between the G natural and the G sharp.
If you make the grace note unslashed, then it should sound on the beat (as an appoggiatura), and you can then adjust the start positions of the other notes in the chord using the “played durations” mode in the Key Editor so that they sound at the same time.