Are these breakers single-pole or double-pole?
Those 3 breakers are two-pole breakers.
I see piggybacking off an existing breaker is indicated as permitted in the installation instructions, installation instructions are part of the NRTL Listing. You probably wouldn't have a function problem but you could run afoul of the Code if the installation instructions for the other item requires a dedicated circuit.
Landing a second wire under the breaker termination is also subject to the Listing of the breaker, most breakers also have the restrictions on the breaker. Schneider Square D QO breakers &quot;have pressure plate terminals suitable for single or two-wire terminations&quot;  There is a chart that shows minimum size is #14. https://download.schneider-electric.com/files?p_enDocType=Catalog&amp;p_File_Name=0730CT9801.pdf&amp;p_Doc_Ref=0730CT9801 .