My favorite would be [name_f]Grace[/name_f], but you can’t go wrong with any of your choices.
I like [name_f]Cora[/name_f] the best, but I do like all of your choices. I wouldn’t do [name_f]Mary[/name_f] and [name_m]Joseph[/name_m] together if there were only two children, but with other siblings mixed in, the two names together don’t stand out as much to me.
[name_f]Cora[/name_f] is my favorite with your other children, though [name_f]Grace[/name_f] is lovely too. I love [name_f]Mary[/name_f], but wouldn’t use it with [name_m]Joseph[/name_m].
I prefer [name_f]Grace[/name_f] both personally and also for you. [name_m]Henry[/name_m], [name_f]Violet[/name_f], [name_f]Annie[/name_f], [name_m]Joseph[/name_m], and [name_f]Grace[/name_f] sound wonderful together.
I like all of your names but with [name_m]Henry[/name_m][name_f]Violet[/name_f][name_f]Annie[/name_f]* and [name_m]Joseph[/name_m], I would choose…
1 [name_f]Grace[/name_f] - sweet and simple. I think I like it best with [name_f]Violet[/name_f] and [name_f]Annie[/name_f]
2 [name_f]Cora[/name_f] - a little harsher but it goes well with the siblings
3 [name_f]Mary[/name_f] - a wonderful name but not with a family who already has a [name_m]Joseph[/name_m]
[name_m]Just[/name_m] curious - is [name_f]Annie[/name_f] a real-life [name_f]Annie[/name_f] or is it a nn for something else?
I would have picked [name_f]Mary[/name_f], but with [name_m]Joseph[/name_m], I agree that it’s a bit much. First thing I thought of was [name_f]Mary[/name_f]-[name_f]Grace[/name_f], and I see others agree! [name_f]Mary[/name_f]-[name_f]Kate[/name_f] or [name_f]Kate[/name_f] by itself would be lovely too. I personally dislike [name_f]Cora[/name_f], but even putting that aside I don’t think it goes well with the other siblings.
I feel that [name_f]Cora[/name_f] sound the best with you others. They would make a darling sibset!
I find it very amusing that everyone is worried about [name_f]Mary[/name_f] and [name_m]Joseph[/name_m] because my sister’s name is [name_f]Josephine[/name_f] and we’ve never gotten any “[name_f]Mary[/name_f] and [name_m]Joseph[/name_m]” comments. My brother’s name is [name_m]Peter[/name_m] and we’ve gotten a few comments like, “[name_f]Do[/name_f] you have a [name_m]Paul[/name_m]?” or “You need a [name_m]Paul[/name_m]!”, but I personally enjoy that.
With your other kids, I like [name_f]Cora[/name_f] the best, but I really love [name_f]Mary[/name_f] and [name_f]Grace[/name_f], as well! I like [name_f]Grace[/name_f] with [name_m]Henry[/name_m], [name_f]Violet[/name_f], [name_f]Annie[/name_f], and [name_m]Joseph[/name_m] more than [name_f]Mary[/name_f], but they all work well.
I prefer [name_f]Mary[/name_f]. I think it goes really well with the sibset.
[name_f]Annie[/name_f] is an [name_f]Anne[/name_f]. 
We do call her [name_f]Anne[/name_f] once in a while but almost always [name_f]Annie[/name_f] for now.
[name_f]Grace[/name_f] is [name_m]WAY[/name_m] too popular at the moment
[name_f]Cora[/name_f] reminds me of home help (Handmaid’s Tale)
[name_f]Mary[/name_f] is an unsung hero, I’d go with [name_f]Mary[/name_f].
I prefer [name_f]Cara[/name_f] or [name_f]Clara[/name_f] to [name_f]Cora[/name_f]
I like [name_f]Grace[/name_f] best with your sibset but I do love [name_f]Mary[/name_f]!