Your welcome!
Note, I didn’t “recommend” them, I merely showed you a possibility to source odoshi and other DIY parts. Because you are apparently situated in Japan, you should have more options over there.
Cotton is of course much more durable than silk. However, I don’t know what was used on your armor.
You mentioned the color of the lacing and I got your point in this regard, but there is also a trend in restoring real Japanese armor keeping the restored parts visible. Furthermore, silk and cotton as also urushi changing color with age due to several influencing factors. Anyway, we are talking about a replica, so it’s up to you!