Manipulating the legend for a Seaborn Jointplot

I am seeking advice on how to edit the colors of the symbols in my legend when using a seaborn jointplot with several other matplotlib scatterplot layers.

My Specific Question:

> Given the data and the current chart below, how can make an adjustment to the code so that the colors of the latter five points on the legend (e.g., "3", "4", "5", "6", "8") can be changed to gray (i.e., #b9b9bd)?

The reproducible code has been pasted below, but there is a publicly accessible Colab Notebook that can be copied and used for experimentation.

<details>
<summary> Reproducible Example </summary>

# import pacakges
import matplotlib.pyplot as plt
import seaborn as sns
import pandas as pd
import numpy as np
# load the mpg dataset
mpg_df = sns.load_dataset("mpg")
mpg_df = (
mpg_df
.astype({"cylinders":"category"})
)
mpg_df["cylinders"] = (
mpg_df["cylinders"]
.cat
.as_ordered()
)
# establish the markers
_markers_cylinders = {
3:"P", 
4:"d", 
5:"v", 
6:"X",
8:"s"
}
# establish colors for countries
_palette_origin = {
"usa":"#fca847",
"japan":"#8aed7b",
"europe":"#7b81ed"
}
kws={
"s": 225,
"linewidth": 2
}
# plot the jointplot -- establish the figure -- the content of the plot is not needed just the marginal ditributions
jp = sns.jointplot(
data=mpg_df,
x="weight",
y="mpg",
hue="origin",
palette=_palette_origin,
markers=",",
marginal_kws={"fill":True},
color="w",
height=10,
s=1
)
# plot scatter by origin and cylinder as layers on the original jointplot
origin = ["usa", "japan", "europe"]
for nation in origin:
df = mpg_df[mpg_df["origin"] == nation]
for k,v in _markers_cylinders.items():
jp.ax_joint.scatter(
data=df[df["cylinders"]==k],
x="weight", 
y="mpg", 
marker=_markers_cylinders[k], 
c=_palette_origin[nation],
edgecolor="k",
alpha=0.6,
**kws
)
jp.ax_joint.grid(
color="k",
linestyle=":", 
linewidth=0.75
)
han, lab = jp.ax_joint.get_legend_handles_labels()
lab = [
"USA",
"Japan",
"Europe",
"3", 
"4", 
"5", 
"6", 
"8"
]
jp.ax_joint.legend(
han[0:8],
lab[0:8],
title="Origin & Cylinders",
fontsize=15,
bbox_to_anchor=(1.20, 1),
title_fontsize = 14,
markerscale=2.5,
shadow = True
)
sns.move_legend(
jp.ax_joint,
loc="upper left",
bbox_to_anchor=(1.20, 1),
markerscale=0.25
)
plt.show()
plt.show()

</details>

This can be accomplished by reusing the existing handles and then changing the face color of the marker.

han, lab = jp.ax_joint.get_legend_handles_labels()
new_han = [
handles[0],
handles[1],
handles[2],
Line2D([0], [0], marker='P', markerfacecolor='#b9b9bd', markeredgecolor='black', markersize=14, ls=''),
Line2D([0], [1], marker='d', markerfacecolor='#b9b9bd', markeredgecolor='black', markersize=14, ls=''),
Line2D([0], [2], marker='v', markerfacecolor='#b9b9bd', markeredgecolor='black', markersize=14, ls=''),
Line2D([0], [3], marker='X', markerfacecolor='#b9b9bd', markeredgecolor='black', markersize=14, ls=''),
Line2D([0], [4], marker='s', markerfacecolor='#b9b9bd', markeredgecolor='black', markersize=14, ls='')
]
jp.ax_joint.legend(
new_han,#han[0:8],
lab[0:8],
title="Origin & Cylinders",
fontsize=15,
bbox_to_anchor=(1.20, 1),
title_fontsize = 14,
markerscale=2.5,
shadow = True
)