At first that would be fine.
Said that, this is a very specific case where you can use both hreflang and cross domain rel="canonical".
Remember that these two mark-up are totally independent one each other, though.
If you use them both, as I wrote replying to Yusuf, from one side you are telling Google that you want it to show a determined URL for a determined geo-targeted country/language, and from other side you are also telling Google that that geo-targeted URL is the exact copy of the canonical one.
What Google will do will be showing the geo-targeted URL in the SERPs, but with the Title and Meta Description of the canonical one.
One more thing, and this a strong reason for urging a complete translation in a short period of time:
if the content of the URL of the French site, for instance, is in English, you cannot put "fr-FR" in the hreflang, but "en-FR". This is a consequence: that the URL will tend to be shown only for English queries done in Google.fr, not for French queries... and that mean loosing a lot of traffic opportunities.