Yes you can try other ingredients.

Oils - You can substitute for any type of liquid carrier oil. For example, Almond, Jojoba, Strawberry or Sunflower are great options. Just be mindful that different emollients can have a different skin feel

Butter - You can also use Mango Butter in place of the Shea Butter. Cocoa butter is a harder butter so you may need to adjust the recipe as the butters can have different consistencies. 

Essential Oils - you can use an alternative essential oil but ensure you check dermal limits and that it is safe to use.

Emulsifiers - You can try other emulsifying waxes but just be mindful that not all emulsifiers behave the same way. You may need to experiment with different percentages and combinations to find something you like.

Yes you can leave out the essential oil. To ensure that the receipe adds up to 100%, just add the 1% to the oil.

Yes you can use a different essential oil. Just ensure that your chosen essential oil is safe for the skin and check the dermal limits.