Email Notification that is dependent on another list for the Email Template to be sent

Hi,

I would like to ask if you have a better approach in creating an email notifcation via workflow of a list then crosschecking with another list to determine the email template that will be sent. 

Background: 

I created List A, which will be used by users to input names of people who will receive the emails. The List A has the following fields:

• Receipient (Person)
• Type (Choice)
• Sub-Type (Look-Up to List B)

I then created List B which is the source list that will determine which email template will be sent if the field is empty or not. The List B has the following fields:

• Category 1 (Person)
• Category 1 Location (Single Text)
• Category 2 (Person)
• Category 2 Location (Single Text)

Intention:  When a user adds a new item in List A

1. Fills in the Receipient filed
2. Fills in the Type
3. Fills in the Sub-Type

The Workflow will run to check if the selected Sub-Type in List B, with the following conditions: 

• If Category 1 has information use email template 1
• If Category 1 is blank, check Category 2 if it has information use email template 2 
• If Category 1 and 2 has information use email template 3 
• If Category 1 and 2 are blank select use email template 4

I've setup the following variables however, I'm encountering errors that the workflow won't work.

1. Set Category 1 Contact (Variable Single Text)
2. Set Category 1 Location (Variable Single Text)
3. Set Category 1 Contact Email (Variable - Single Text)
4. Set Category 2 Contact (Variable - Single Text)
5. Set Category 2 Location (Variable - Single Text)
6. Set Category 2 Contact Email (Variable - Single Text)

Any help is much appreciated!