I find avocados difficult to bolus for. My usual I:C ratio doesn't work so well for them. I think that might be because our carbs are all net carbs, with fibre deducted. And sometimes, for some people fibre in some foods can be absorbed and raise blood sugar. I think avocado does this to me because I mush it up for guacamole and maybe that allows the fibre to be digested?
If you're having 50g of carbs in a meal you definitely don't need to think about bolusing for protein. Your body wants to get glucose from somewhere. When you're feeding it a reasonable amount of carbs it will be readily available from the carbs eaten. ONLY if you are eating a low carb diet will your body decide it needs to get glucose by performing the process of gluconogenesis on the protein eaten, turning the protein into glucose. This process is the difficult way for the body to get glucose. It's not going to bother doing the difficult process if there is glucose readily available in carbs eaten.
Fat shouldn't impact on your bolus dosage. But may make you consider bolus timing: possibly half the bolus before and half the bolus after eating because a high fat content meal will slow down the carb action.