Unfortunately I couldn't tell you that. I just finished looking for your gggrandfather on the LDS CD set - no luck, so that means he (the family) was either missed by the census, or he was going by a different given name. There are plenty of Anthonys in both LA and MS. As I mentioned earlier, there are 64 in the Louisiana 1870 census index - I would imagine one of them is him (his father in the index). The only way is to look up all 64 of them to find out.
I also looked for your gggrandmother, Helland, as it is spelled in the 1900 census. Nothing, in either LA or MS for 1880, except two white women in MS. She may have been using a different given name also. I've run into this problem a number of times.
If you have access to ancestry.com, you can first check the index to find the locations of the Anthonys in Louisiana in 1870, then look them up on the images on-line. Many of them seemed to be located in the parishes around New Orleans, but there were some scattered all over the state.
The other option, if you don't have ancestry.com access, is to go to your local LDS family history library and look at the microfilm there - it's free. I'm sorry I couldn't be of more help.
Good luck.