1) The most efficient way to import census records is via a subscription to ancestry.com. Through FTM's integration with ancestry.com, you can add a census record for a father, mother, and eight children by adding 10 names facts (or discarding them or merging them), 10 birth date facts, and 10 residcence facts, along with the accompanying 30 source citations and the single census media item attached to each of the source citations by going through a series of screens to select whether to add, merge or discard the appropriate facts. Then push a merge button to make it all happen while you sit back and watch. I sometimes have a problem with the source citations provided by ancestry, but you can edit all 30 citations at once by just editing one and they will all change - as they are clones of each other.
2) If you choose to not use ancestry, you can setup the 3 facts for name, birth year and place, and residence for each of the 10 people. You would then create one source citation for this record, attach the media to that citation then copy and paste this citation, with media to each of the 30 facts. You create the source first, then the citation, then, select the citation and click on the media tab and click to add the media item to the citation.
3) You can make step 2 more efficient by copying and pasting a single identical fact relative to the residence fact (or census fact if you use that). You do this by first entering manually one fact for the census, then select the fact, with the associated source citation, with the appropriate source media attached to the source citation, at the person page and then right click copy and then right click paste. This will bring up a screen of this person's immediate family. You choose which of this person's family you want to paste this fact to. Of course, this won't work on the name and birth facts, since everyone in the family presumably has a different name and birth fact. You still have to set those facts up one at a time, but you can copy and paste the associated census source citation, with media attached, to each of those facts.