[1] The verb ὠθέω has two future stems: ὠθησ- and ὠσ- (as if from ὤθω ). See LSJ s.v. for the attestation of the various forms (web address 1). The form ὠθήσομεν occurs at Aristophanes, Ecclesiazusae 300 (in a lyric passage, see web address 2).
[2] The hypothetical form ὤθω is glossed by the later verb πρώθω (not in the LSJ but in Lampe). This particular passage is from the Lexicon Ambrosianum ineditum 44.
[3] Sc. because ὠθέω is a contract verb. This passage is from the Pseudo-Herodian Partitiones 251.