Sounds like a tasty idea. I'd skip the lotus root starch because starches need to be converted in the mash to fermentable sugars. You can take or leave the maltose, it will be nicely fermentable, but it probably doesn't add much flavor. I believe Extreme Brewing has a recipe with Chinese Yellow Lump sugar, sounds like what you have. The brown sugar should be a tasty addition as well.
What is the weight of the brown sugar? You are probably pushing the upper limit in terms of simple sugars. I'd highly suggest adding some yeast nutrient with all that extract and sugar.