I don't think you'll be able to use the Children.WIthAllData method in this case, you're going to need to generate a new DocumentHelper.GetDocuments() query, using either the current page's NodeAliasPath, NodeID, or NodeGuid, as these are shared amongst cultures. NodeAliasPath will probably be the easiest, as it has a DocumentHelper.GetDocuments().Path(ParentPage.NodeAliasPath, PathTypeEnum.Children)
So your full query would look like:
DocumentHelper.GetDocuments()
.Types(new string[] { "My.PageType", "My.PageType22"})
.WithCoupledColumns(true)
.Path(ParentPage.NodeAliasPath, PathTypeEnum.Children)
.Culture(cultureName)
.CombineWithDefaultCulture(true)
.Published(!latestVersionEnabled)
.LatestVersion(latestVersionEnabled);