The status of the vowels is controversial. Rosen (2007) and Rhodes (2009; French words only) have different views, and the author of these lines has a different opinion again.
It must be remarked here that Standard French /e:/ is realized as /i:/ in Michif (li tii 'tea', French le thé, zhurnii 'day', French journée).
The phoneme /e/ tends to be long, and contrasts with /ɛ/ which tends to be short, but there is quite a bit of phonetic overlap.
In French-origin words like nweezoo 'bird', mafwee 'my goodness', peer 'father' the long vowels tend to be closer to /ɛ/.
For Cree origin words, the long vowels are closer to /e/ and the shorter closer to /ɛ/. Some examples include: ee-kii-pee-tuhtee-yen 'when you came here', kiweetaak 'let's go home', shipweehtee 'leave!'