Including cauliflower rice is a fantastic idea to add volume and more micronutrients! To do this, you can halve the amount of basmati rice and add the equivalent weight in cauliflower rice. It cooks very quickly, so you can simply stir it in during the last five minutes. Red lentils are a perfectly fine substitute; just keep in mind that they soften much faster than green ones. I would recommend checking for doneness around the 5-8-minute mark. For the quantity, stick to the same amount as you would have used for the green lentils. let me know how it goes ! :)