Tbh, NSO would be way cooler than WFC - WFC is already supported by Wiimmfi + RC24 + WiiLink24 + DoujinSoft Store.
There are currently only 2 known replacement projects for NSO in development or online - Open Course World for Mario Maker 2 and an alternate server for Mario 35 – nothing that is supposed to cover NSO in its entirety.
Fun fact: Even though almost all optical disc standards with “RW” or “RE” are rewritable, DVD-RW actually isn’t - it’s just an extension of the DVD-R standard.
For rewritable DVD, you’re looking for DVD-RAM or DVD+RW (not “-RW”).
You could upgrade it to 7 or even 10 if possible. Also I recommend you check out Legacy Update. It’s a Windows update revival for older versions like Vista.