You could try sunflower seed flour as it's a one-for-one sub for almond flour. Oat fiber is a good sub for coconut flour but it's not a one-for-one. As for oil, you should be able to use a seed based oil even though they aren't recommended for keto.

I’m extremely allergic to all forms of anything ALMONDS, anything COCONUT and anything AVOCADOS (ie: flours, milks, oils, sprays). My nutritionist wants me to use Fairlife Milk for cooking because it has such low carbs.
Do you have any suggestions for substitutions in recipes for flour, spray release like Pam and oils?
Thank you!

I use Ghiradelli cocoa as I find it tastes better than Hershey's.

The molten part results from uncooked batter inside the cake. You could fully cook the cake then fill it with a filling using a pastry bag.

I am not a f!n of chocolate, can this be made using your caramel sauce?

Sorry about that! You do need to be careful not to overcook and keto desserts tend to be on the less sweet side. You can always add in a few drops of liquid sweetener if needed. I don't recommend adding more erythritol based granular sweetener as it can crystallize if too much is added.

It's best to make this just before serving. If making ahead, I'd recommend taking out of the oven early so you can place in a warm oven before serving and not cook the center. Preparing the batter ahead may also work.

Wide mug is fine. However, the cake will cook fast on high power so you may want to try reducing the power setting on the microwave so you don't overcook.