I don't think that estimate time is any good, mine says 3 days and I am waiting for an interview as well. When I asked the live Agent on Emma, they said I should not worry about that estimated time at all as it is not correct
For employment I would submit as separate - as this is not a typical employment and with separate contracts. You may also list the periods you were unemployed just to be honest. At the end it doesn't really matter as you are married to a USC
I know the estimated time on USCIS account doesn't mean anything. But I did see my estimated time updated -Estimated time* until case decision:
approx. 2 months