I've watched most of their CL matches and some Ligue 1 ones, they are fast and most of the teams they've played against gave them space as-well which is not or shouldn't be the case with Juve.
They love playing counter attack football and would even invite you to play one against them for opening up so many spaces, they run too many risk because they know they have fast players.
Honestly, I could see only one risk in the match, it's not Mbappe he's not going to damage this defense if Messi, Neymar Suarez couldn't, if Juve don't use their chances to score like what happened vs Barca in the 2nd leg then yes, there could be a risk, but I see Gonzalo, Dybala, Cuadrado scoring at least one in the first match, that's in the worst case scenario shouldn't be that bad with a clean sheet.