wylm is a variant of wilm, welm, wælm = surging, boiling water or other liquid. See ME walm, welm; lemmawalmin the MED. Possibly related to well and German Quelle., related to the verbs quellen and wallen. A derived word with the -m suffix is German Qualm = thick smoke.
ed is a variant of ad = funeral pyre; here simply meaning fire. Also survived into ME; see lemma ad in the MED.