For the ice cream: add the frozen banana to a food processor. Process on high until smooth and creamy, scraping down the sides as needed. Add vanilla and process until combined. Transfer to a freezer-safe container and freeze for at least 30 - 60 minutes.
For the coconut cream: remove the lid from the can then carefully scoop out the solid bit from the top into a bowl, leaving the coconut "water" in the bottom of the can. Using an electric mixer, beat the coconut cream until fluffy. Whip in the monk fruit extract (or syrup), taste and adjust sweetness if needed. Place in the fridge until ready to assemble the sundaes.
For the chocolate sauce: whisk together all the ingredients until smooth. Leave at room temperature so the coconut oil doesn't harden.
For the peanut butter sauce: stir together peanut butter and water until you get a "pourable" consistency. Again, store at room temperature until ready to serve.
To serve: Divide the banana ice cream among two sundae dishes. Top with a large dollop of whipped cream (you'll have leftover), a drizzle of both the chocolate and peanut butter sauce, and top with your desired toppings.