1)
Here it says "Difas". In Bereishis 10:3, it says "Rifas"!
1.
'Rashi': Initially they were Rafin (soft), and did not overpower Yisrael. In the end, they were full of Dofi (blemish) and Ri'u'a (shattered).
2.
On the coming verse, Radak explains why sometimes Reish switches to Dalet when a name appears elsewhere (refer to 1:7:2:3). Here, he only remarked that here it has a Reish! Perhaps he relied on what he wrote below. (PF)
3.
Malbim (5): When Ezra wrote Divrei ha'Yamim, they were called Difas.
