Resident permit B after deregistration

How hard is it to re-instate my residence permit?

If you de-register, permit is invalidated - You will have to show evidence of employment, to obtain another permit

During job application procedures when asked if I have: valid permits to work in CH....what should I put? Yes or No?

You do not have a valid permit. If you had stayed registered, then by law you must to continue to pay health insurance and tax.

During job application procedures when asked if I need: sponsorship? What should I put? Yes or No?

Yes, it's that evidence of employment, that you require. For EU Citizen, the criteria will be the same as when you obtained the invalidated permit

@CoolAndrea90

As EU citizen you can come here and hunt for a job at any point in time.

For the B, you better get a job offer.

At your job applications, are you eligible, it will be a Yes

Sponsorship No. You pay the fee for the B, not the employer.

You do not require working visa.