A question about Steam Greenlight fee

I assume that yes. But I have no idea.

I'm pretty sure it's one per person, else those virus greenlight games would have been bigger imo. nope.

Also it's only 90€ which is alright

You can use the new account to purchase the fee and post your item and then add other accounts as contributors to the item in order to moderate, post announcements, etc.

Still it's just 90€ to buy another one

it's only 90? brb stealing unity assets to make a "game"