Washed their stripes (elousen apo tōn plēgōn). Deissmann (Bible Studies, p. 227) cites an inscription of Pergamum with this very construction of apo and the ablative, to wash off, though it is an old verb. This first aorist active indicative of louō, to bathe, succinctly shows what the jailor did to remove the stains left by the rods of the lictors (Act 16:22). Niptō was used for washing parts of the body.
And was baptized, he and all his, immediately (kai ebaptisthē autos kai hoi autou hapantes parachrēma). The verb is in the singular agreeing with autos, but it is to be supplied with hoi autou, and it was done at once.