Hi Welcome to BW forums
Looks like you're doing great!!
How about doing another feed just before she sleeps, so in addition to the 6pm feed before bath you also do one after bath, then song and sleep? The two feeds will be quite close together, maybe consider it a split-feed. It might help her to tank up rather than wake for another E at 8pm.
If she does wake though, personally I'd just go for the NF at 8pm as the rest of routine and the journey towards self settling sounds like it is going great so I probably wouldn't want to disturb that.
There's a chance that if you do the 8pm feed in dim light and take her straight back to her cot she will go to sleep again rather than treating the 7pm BT as a nap.
There's also a chance (especially if she takes another feed just prior to sleep) that you could try a W2S before 8pm, so just slightly disturbing her to start a new sleep cycle. This could help her to stay asleep through the 8pm wake up but it's important to note that as a result she may wake at another time and need a feed.
It sounds like she is already going as long as she can overnight between feeds so if you could get that last feed closer to 7pm, then the DF at 10pm then hopefully she will do that long stretch to 3am or 6.30am (both considered as "sleeping through" which is a 5hr stretch).
I hope this helps.