If a person, other than a petitioner under section 723.09 of the Revised Code, owning a lot in the immediate vicinity of a street or alley prayed to be vacated or established, claims that he will sustain damage thereby, the court of common pleas may proceed to hear proof in reference thereto and may render judgment against the petitioners for such damages as it thinks just, which damages shall be assessed ratably against the petitioners by the court according to the value of the property owned by them as it stands taxed on the tax list of the county, and a jury may be demanded as in other cases. The court shall, when necessary, appoint a guardian ad litem for all minors or persons of unsound mind who are interested in the premises.