Liverpool has't stopped yet. They're trying to hunt more talent to be recruited. They have done with Frimpong, Wirtz (medical check up), Kerkez, (still in the negotiation), and add Isaak as their last target. Their target to sign Isaak from Newcastle is just getting even more possible with Nunez who is still in the process to go to the Napoli(i expect him to play for that italian club).
I think we will see Isaak to wear Liverpool's jersey as he has open the move to the any big club that play in UCL.
I have looked into some reliable sources but couldn't see an update like Liverpool is interested. But if they are then they will need to pay a sum similar to the one they paid for Wirtz most probably.
Even if they have the money for it, I don't know whether it can be allowed. How much do FFP rules let teams spend? Or should I say how much should the profit/loss balance be for teams?
His current market value is 120 million euros. I don't think Newcastle would let him go for less...