For sure. Limes are slightly higher in net carbs than lemons, but using one or the other won't make a very significant differnce to the macros overall.

Yes. If you're not into tangy flavors, you can omit a lime or increase the sweetener. 

Yes. To make this chia pudding lower in fat/calories you can replace some, or all, of the coconut milk with soy/pea milk. Note that this may make the pudding seem tangier as the fats in coconut milk help to coat the tongue and mellow the acidity some. Replacing half of the coconut milk with soy/pea milk reduces the calories per serving to about 170. Replacing all of the coconut milk reduces the calories to 135. The protein in the pudding will aslo increase slightly and the net carbs decrease slightly.

I'm referring to your preferred net carb-free sweetener. My first choice of sweetener is granulated allulose because it is the most similar in taste and behavior to sugar. But allulose isn't available everywhere. Other granulated options are erythritol, an erythritol blend, or xylitol. Pure low-bulk/highly-concentrated options are pure monk fruit or pure stevia. For these, you will have to look at your packaging and adjust the quantity needed for the recipe. For simplicity, you can assume that the amount of allulose I've listed is equivalent to sugar. Sucralose or another artificial sweetener is also an option.

When available, I typically use NCCDB data in Cronometer to calculate calories and macros. There are a few items that I choose to use label or custom data for instead, despite the availability of NCCDB data. This is usually because I've found that the label data differs substantially and consistently for these foods. In this recipe, I have used label/custom data for the extra-firm silken tofu (Mori-Nu), coconut milk (Aroy-D), and chia seeds (Bob's Red Mill). There is no data for lime zest and so I have used lemon zest in its place. Be aware that both NCCDB and label data change over time and so what I've given here may have changed since the recipe was first published.

Counting calories and macros can negatively affect mental health by being time-consuming and by creating an obsession with inconsequential levels of detail. In an effort to mitigate this, numbers are rounded. In most cases, numbers equal to or greater than 10g are rounded to the nearest whole number (e.g. 10g, 11g, 12g, etc.) and numbers below 10g are rounded to the nearest 0.5g (0.5g, 1g, 1.5g ... 9g, 9.5g). Any numbers below 0.5g are given as is (e.g. 0.1g, 0.2g, etc.). Calories are rounded to the nearest multiple of 5.