That sounds like an excellent answer.
Well two excellent answers actually.
The legal terms are especially helpful.
At this time, the Dwr-Y-Tryges are not at war with Rome, since we have very little contact. Our hunting dogs are much prized in Italia, and our tin is vital for making bronze, and of course we have a little silver and gold. In exchange we get wine, and luxury goods such as fine ceramics. I love your drinking vessels, so refined.
Obviously there are tribes which have in the past been hostile to Rome, but I trust the likes of Brennus are long forgotten, at least in official circles.
Gallia Narbonensis has long been accepted as a Roman province and I am sure the remainder of Gaul can expect nothing but good relations with the Republic, for many generations, since both sides would have too much to lose from any conflict.
We have a young and upcoming warrior called Vercingetorix who it is said is unbeatable in battle.
However, supposing they went as merchants and ran into some trouble in Ostia involving an (unfounded) accusation of theft, say, of exotic animals.
Would that pose a problem if they were to attempt to continue to Rome or would the anonymity of a big city be sufficient to cloak them?
Also what is the Roman attitude at this time to such things as (for want of a better word) witchcraft?
Not that my family ever has any dealings with the supernatural, especially NOT Druids.