Mid lax vowels in open syllables are marginal. /ɛ/ occurs in two morphemes even in open syllables, so is accepted here as a phoneme; /ɔ/ only occurs in open syllables due to allophonic effects and reduplication (of /au/), so it isn't.
High vowels only contrast for tenseness in closed syllables; if high tense vowels in closed syllables are actually VV sequences, /ɪ ʊ/ can be analyzed away.