Problem:
The user has a custom taxonomy that has months as terms. Inside a view's taxonomy filter, he would like to display them in months order and spread them in two columns

Solution:
Toolset does not offer a way to sort taxonomy terms in a filter. Use a third-party plugin to enforce your custom taxonomy order. Examples:

https://wordpress.org/plugins/custom-taxonomy-order-ne/

• https://wordpress.org/plugins/simple-taxonomy-ordering/
• https://wordpress.org/plugins/wp-term-order/

To spread the filter checkboxes across two columns use Custom CSS. Check the example in https://toolset.com/forums/topic/sorting-months-search-field/#post-2105591