Change legend labels and position dodge - r

Question

I created with ggplot an interaction plot and added with a different dataframe outliers into the same plot. I want to change the legend's labels (yes and no), but a new legend is added instead of changing them. Here is the Code:
the theme I'm using:
theme_apa(
legend.pos = "right",
legend.use.title = FALSE,
legend.font.size = 12,
x.font.size = 12,
y.font.size = 12,
facet.title.size = 12,
remove.y.gridlines = TRUE,
remove.x.gridlines = TRUE
)
the plot:
InteractionWithOutliers <- ggplot() +
geom_line(data=data2, aes(x=Messzeitpunkt,
y = Sum_PCLMean,group = TB2,linetype=TB2),) +
scale_color_manual(labels = c("test", "test"),values=c('#000000','#000000'))+
geom_point(data = outliersDF, aes(Messzeitpunkt,Sum_PCL,
shape=TB2, color=TB2, size=TB2),) +
geom_point(data = data2, aes(Messzeitpunkt,Sum_PCLMean,
shape=TB2, color=TB2, size=TB2), ) +
scale_shape_manual(values=c(15, 17))+
scale_size_manual(values=c(2,2)) +
ylim(0, 60) +
scale_x_continuous(breaks = seq(0,2)) +
geom_errorbar(data=data2,aes(x = Messzeitpunkt,ymin=Sum_PCLMean-Sum_PCLSD, ymax=Sum_PCLMean+Sum_PCLSD), width=.2,)
InteractionWithOutliers + theme_apa() +
labs(x ="Measurement Period", y = "PTSS mean scores")
Image of the Graph:
Furthermore, when i try to use position dodge to split the position of the interaction plot and the outliers, not everything moves the same way.
Code:
InteractionWithOutliers <- ggplot() +
geom_line(data=data2, aes(x=Messzeitpunkt,
y = Sum_PCLMean,group = TB2,linetype=TB2),position = position_dodge(width = 0.4)) +
scale_color_manual(labels = c("test", "test"),values=c('#000000','#000000'))+
geom_point(data = outliersDF, aes(Messzeitpunkt,Sum_PCL,
shape=TB2, color=TB2, size=TB2),position = position_dodge(width = 0.4)) +
geom_point(data = data2, aes(Messzeitpunkt,Sum_PCLMean,
shape=TB2, color=TB2, size=TB2),position = position_dodge(width = 0.4) ) +
scale_shape_manual(values=c(15, 17))+
scale_size_manual(values=c(2,2)) +
ylim(0, 60) +
scale_x_continuous(breaks = seq(0,2)) +
geom_errorbar(data=data2,aes(x = Messzeitpunkt,ymin=Sum_PCLMean-Sum_PCLSD, ymax=Sum_PCLMean+Sum_PCLSD),
width=.2,position = position_dodge(width = 0.4))
InteractionWithOutliers + theme_apa() +
labs(x ="Measurement Period", y = "PTSS mean scores")
Thank you for your help!
Edit: Data for the Outliers:
Messzeitpunkt Sum_PCL TB2
0 38 no
0 37 yes
0 40 yes
0 41 yes
0 38 yes
1 56 no
1 33 no
2 39 no
2 33 no
Data for the interaction plots:
Messzeitpunkt Sum_PCLMean TB2 Sum_PCLSD
0 9 no 11
0 12 yes 11
1 9 no 15
1 18 yes 16
2 8 no 12
2 14 yes 12

Answer 1

Merging legends can sometimes be painful. If your variables are already labelled (like in your example), then you also don't need to stipulate breaks or labels. (see first example).
However, a good rule is - don't add an aesthetic if you don't really need it. Size and color are constant aesthetics in your case, thus you could (and should) add it as a constant aesthetic outside of aes.
P.S. I have slightly changed the plot in order to make the essential more visible. I personally prefer to keep my plots in an order geoms->scales->coordinates->labels->theme, this helps me keeping an overview over the layers.
library(ggplot2)
data2 <- read.table(text = "Messzeitpunkt Sum_PCL TB2
0 38 no
0 37 yes
0 40 yes
0 41 yes
0 38 yes
1 56 no
1 33 no
2 39 no
2 33 no", head = T)
outliersDF <- read.table(text = "Messzeitpunkt Sum_PCLMean TB2 Sum_PCLSD
0 9 no 11
0 12 yes 11
1 9 no 15
1 18 yes 16
2 8 no 12
2 14 yes 12", head = T)
ggplot() +
geom_line(data = data2, aes(
x = Messzeitpunkt,
y = Sum_PCL, group = TB2, linetype = TB2
)) +
geom_point(data = outliersDF, aes(Messzeitpunkt, Sum_PCLMean,
shape = TB2, color = TB2, size = TB2
)) +
geom_point(data = data2, aes(Messzeitpunkt, Sum_PCL,
shape = TB2, color = TB2, size = TB2
)) +
## if your variable is labelled, no need to specify breaks or labels
scale_color_manual(values = c("#000000", "#000000")) +
scale_shape_manual(values = c(15, 17)) +
scale_size_manual(values = c(2, 2))
## Better, if you have constant aesthetics, not to use aes(), but
## add the values as constants instead
ggplot() +
geom_line(data = data2, aes(
x = Messzeitpunkt,
y = Sum_PCL, group = TB2, linetype = TB2
)) +
geom_point(data = outliersDF, aes(Messzeitpunkt, Sum_PCLMean,
shape = TB2
), size = 2) +
geom_point(data = data2, aes(Messzeitpunkt, Sum_PCL,
shape = TB2
## black color is default, this is just for demonstration
), color = "black", size = 2) +
scale_shape_manual(values = c(15, 17))
Created on 2022-07-15 by the reprex package (v2.0.1)