How do I edit these features of a network plot in R?

I am conducting some social network analysis on social mobility data. I am using this program to identify clusters of related occupations (i.e. clusters of occupations that have high levels of intergenerational transfer between them).

This program uses a version of ggplot to create its social network plots. The code I am using is as follows:

#MONECA analysis to find number of segments & assign occupations to segments (mob.mat is a dataframe containing the cross-tabulation of origin and destination occupations)
segments<- moneca(mx = mob.mat, segment.levels = 3, cut.off = 1, mode = "symmetric",
       delete.upper.tri = TRUE)

#network plot
edges <- segment.edges(segments, cut.off = 1, method = "all", segment.reduction = 0, level = 1)

finalMONECA <- gg.moneca(segments, level = seq(segments$segment.list),
                         layout = layout.matrix(segments), edges = edges,
                         mode = "directed", vertex.size = "total", vertex.fill = "segment",
                         vertex.alpha = 1, vertex.color = "black", vertex.shape = 21,
                         show.edges = TRUE, edge.size = 1, edge.alpha = "weight",
                         edge.color = "grey76", edge.line = "solid", show.text = FALSE,
                         text.size = 3, text.color = "black", text.alpha = 1, text.vjust = 1.5,
                         show.borders = TRUE, border.size = 1, border.fill = NA,
                         border.color = "black", border.alpha = 1, border.padding = 0.7,
                         border.text = TRUE, border.labels = "segments", border.text.size = 4,
                         border.text.color = "black", border.text.vjust = -0.2,
                         border.text.hjust = 1, midpoints = TRUE, 
                         midpoint.arrow = arrow(angle = 20, length = unit(0.33, "cm"), ends = "last", type = "closed"),
                         edge.text = FALSE, edge.text.size = 3, edge.text.alpha = 0.9, legend = "side")

This works well enough and produces the follow plot:

moneca network plot

However, I would like to alter the plot in a couple of ways and I am struggling to do this. This is an idiosyncratic package that I imagine few people have used, but I'm hoping something can be generalised from a knowledge of how network plots work (or how ggplot works more generally).

First, I would like to add custom labels to the clusters (border.labels). Currently this is drawn from 'segments', which just has the code numbers for the clusters. However, I would like to manually create a label for each cluster and add it to the plot.

Second, I would like to change the fill of the nodes to be greyscale. It is currently coloured based on the cluster (segment) the node belongs to. I would like to maintain this scheme but make the colours within it greyscale.

Any help would be very much appreciated! I am mostly a Stata person so I an somewhat at sea when it comes to R.

To amend the colours, I have tried using the segment.colors command from within the moneca package, which says it creates a grey scale for the segments. However, I have no idea how to pass the output of this command through to the plot.

I haven't used this package before, but since it produces a ggplot object, it can be amended post-hoc even if the parameters of the wrapper function don't do all you want them to.

Suppose I want to replace the nodes with the following labels:

labels <- c("Forrest Gump", "The Shawshank Redemption", 
            "The Perks of Being a Wallflower", 
            "The Dark Knight", "Changeling", "This Boy's Life", 
            "It's a Wonderful Life", 
            "The Silence of the Lambs", "8 Mile", "The Breakfast Club", 
            "Django Unchained", 
            "Silver Linings Playbook", "The Shining", "Seven", 
            "American Beauty", 
            "Pulp Fiction", "Zero Dark Thirty", "Argo", "The Hurt Locker", 
            "The Godfather", "The Town", "The Departed", "Scream", 
            "Up in the Air", 
            "What's Eating Gilbert Grape", "Lost in Translation",
            "The Conjuring", 
            "Juno", "Stand by Me", "The Green Mile", "Super 8", "
            Jarhead", 
            "Misery", "Fight Club", "Shutter Island", "Lawless", 
            "Winter's Bone", 
            "Taxi Driver", "Saving Private Ryan", "Black Swan",
            "Inception", "Boogie Nights", "50/50", "Brothers", "Blood Diamond", 
            "A Few Good Men", "Gladiator", "Law Abiding Citizen", 
            "Lakeview Terrace", 
            "Glory Road", "Rate")

It turns out the labels are stored in the label parameter of the aes_params of the 8th and 10th layers of the output. So we can over-write them as follows:

finalMONECA$layers[[8]]$aes_params$label <- labels[1:40]
finalMONECA$layers[[10]]$aes_params$label <- labels[41:51]

Now we can plot finalMONECA, making the fill grayscale as requested (though there are literally 40 shades of gray to be colored, so this is next to useless)

finalMONECA + scale_fill_grey()