For Adrenaline interaction, the series of attacks caused by Adrenaline proc forcibly-limited (LoL term incoming) on-hit effects on the first, original attack and the last attack.
This means that a Forest Scorpion with Adrenaline will poison the enemy twice, and a Forest Scorpion with Adrenaline that was just frozen last turn will poison the enemy once.
So there are two ways to go about this interaction.
First, if Swift is an attack-count multiplier on a higher level than Adrenaline, as you've implied in the notes, then since there is no precedence in the game then you can do whatever you want, such as having Adrenaline proc'ing on the first, original attack but not the second, extra Swift attack.
However, second, if you actually wanted to mimic the interaction of Adrenaline+Venomous, then Swift would be an on-hit effect on a lower level than Adrenaline, proc'ing on the first and last hit.
