Sholom Rav.

I have to agree with you that the phrase as it stands, besides being 'improper', as you say, also does not fit in with the surrounding text.

I would therefore suggest that 'bas Meichasl u'Meivad' is a printing error which ought to read 'bas Me'evad u'Meichal'. One does, from time to time, come across errors of this nature which eluded the commentaries.

I heard that when a certain Talmid-Chacham remarked to the Chazon Ish that an obvious printing error Was not corrected by the Rashash, the latter replied 'Then one must oneself be a Rashash'.

Wishing you a Chag Kasher ve'Samei'ach

Eliezer Chrysler.