sacerdotem: this could be a cognomen and it does occur as such, although only twice, in the area covered by NPEL. In view of fes- in line 3, however, it seems more likely to refer to a priest.
Verecundum: it is possible that the reference is to Iulius Verecundus, prefect of the First Cohort of Tungrians (see 154.2-3 and 210-2), although the cognomen is very common. The presence of the letter at Vindolanda suggests that Verecundus ought to be somewhere else; since it is attributed to Period 3 and it is probable that the evidence for his presence at Vindolanda belongs in Period 2, it may well be that he and his unit had moved on or that he had moved to a different unit.
praef(ectum): the initial p is obscured by dirt but there is no doubt about the reading. Abbreviation of the word in the body of a letter is noteworthy.
de fes-: it is likely that we have a noun in the ablative case and the most probable restoration must be festo or festis.