Is it logical/ethical to hire candidate on lower pay scale than the previous employment job?

Of course it's not logical or lethical 

Based on the experience/improvement of this person in his position. If they earn the raise/high salary then it's ok. You need to focus more on yourself and not to be involved in other's personal issues including salary which is highly confidential.

1. I think it is good and experiance very imprtant

مهارات التسويق لبيع منتجات أو منتجات أو بضاعه وسوبرات ملابس

What somebody earned in their previous job is none of your business.

As an aside, the system of paying people based on an increase from their previous job is utterly irrational - it penalises the good people (who do not get the increase they deserve) and rewards the semi-competant (by giving them an increase they do not deserve).