Newcastle are also rumoured to be after Neymar these days by the way. Actually they might be able to more convincing to him as they have joined the Champions League. But Neymar would ask for some guarantees I assume. He might ask for a solid improvements in like nearly every area of their lineup. I wouldn't be surprised with such demand because Newcastle really need it to maintain consistency.
Newcastle are a very rich team now you know so I'm expecting them to build a squad that can do well not only in the Premier League but also the Champions League. If they build such squad then the only worry could be the chemistry among players. As long as they have a solid chemistry they should be good to go.
The potential signing of Neymar for Newcastle now looks more like a symbolic gesture than a real belief that one such player will win a bunch of titles for the club. Here, rather, the same motivation slips through as in the case of Neymar's move to Paris Saint-Germain at the time. The club wanted to show with such a gesture that it is already a club of another higher level, since it can allow signing a player of this class. Similarly, everything can happen again in the case of Neymar, and having a player of this class in the squad can then help with inviting other superstars to the team in the future.