#MATL, 32 41 43 bytes

jk'^(2|t[ow]?o|t0),b(e?e?|3)$'XX 

Same approach as @DigitalTrauma's Retina answer. Inputs are separated by a comma. Truthy output is a string with the two inputs lowercased; falsy is no output.

Try it online!

j % input as a string k % convert to lowercase '^(2|t[ow]?o|t0),b(e?e?|3)$' % regular expression to match the two inputs XX % match regular expression 

MATL, 32 41 43 bytes

jk'^(2|t[ow]?o|t0),b(e?e?|3)$'XX 

Same approach as @DigitalTrauma's Retina answer. Inputs are separated by a comma. Truthy output is a string with the two inputs lowercased; falsy is no output.

Try it online!

j % input as a string k % convert to lowercase '^(2|t[ow]?o|t0),b(e?e?|3)$' % regular expression to match the two inputs XX % match regular expression 

#MATL, 32 41 43 bytes

jk'^(2|t[ow]?o|t0),b(e?e?|3)$'XX 

Same approach as @DigitalTrauma's Retina answer. Inputs are separated by a comma. Truthy output is a string with the two inputs lowercased; falsy is no output.

Try it online!

j % input as a string k % convert to lowercase '^(2|t[ow]?o|t0),b(e?e?|3)$' % regular expression to match the two inputs XX % match regular expression 

#MATL, 32 41 43 bytes

jk'^(2|t[ow]?o|t0),b(e?e?|3)$'XX 

Same approach as @DigitalTrauma's Retina answer. Inputs are separated by a comma. Truthy output is a string with the two inputs lowercased; falsy is no output.

Try it online!

j % input as a string k % convert to lowercase '^(2|t[ow]?o|t0),b(e?e?|3)$' % regular expression to match the two inputs XX % match regular expression 

#MATL, 32 41 43 bytes

jk'^(2|t[ow]?o|t0),b(e?e?|3)$'XX 

Same approach as @DigitalTruma's Retina answer. Inputs are separated by a comma. Truthy output is a string with the two inputs lowercased; falsy is no output.

Try it online!

j % input as a string k % convert to lowercase '^(2|t[ow]?o|t0),b(e?e?|3)$' % regular expression to match the two inputs XX % match regular expression 

#MATL, 32 41 43 bytes

jk'^(2|t[ow]?o|t0),b(e?e?|3)$'XX 

Same approach as @DigitalTrauma's Retina answer. Inputs are separated by a comma. Truthy output is a string with the two inputs lowercased; falsy is no output.

Try it online!

j % input as a string k % convert to lowercase '^(2|t[ow]?o|t0),b(e?e?|3)$' % regular expression to match the two inputs XX % match regular expression