score:6
I've found the answer on the Eurostar website, which it turns out has detailed information on facilities in all their stations.
In short, there are seats and vending machines, but nothing else - no lounge or shops.
Checkin at Lille is the same as everywhere else, 30 minutes, or 10 minutes for Business Premier/Carte Blanche. (Ski services look to be special thought, but they don't apply to Lille)
For the details on what's in Lille, this is what Eurostar have to say:
Our lounge in this European travel hub offers comfortable seating and food and drink vending machines.
Shops and cafés: There are currently no retail facilities in the Lille Europe departure lounge other than vending machines, so if you fancy anything more substantial than a chocolate bar be sure to stock up before you check in.
Refreshingly detailed and honest!