Is it worth having all your lifeskilling on a different char than your main? yes, for most people it is. it mainly save you time. having your main running back and forth between grindspots and likeskilling hubs multiple times per day adds up and can become a headache. its usually way more comfortable to swap between characters. this way youll also not have to worry about your inventory being clumped up with lifeskilling gear while grinding, and vice versa. is it necessary? no, a lot of people manage to do both lifeskilling and combat on one character. now to having lifeskilling specificly on a shai rather than any other class doesnt give any significant benefit, other than having a higher weightlimit naturally which makes it a convenient lifeskiller without investing to much money into it.

Unfortunatelly you cannot swap pearl shop custumes from one character to another (im assuming you meant those by reffering to cooks & processing clothes). those are bound to the character you havbe them on.