It makes 0 sense for anyone to lend such a license
Exactly, lending a license is illegal if I recall because that means that you're trying to impersonate another business in favor of your business so it can operate normally. Any form of evasion to register a license is illegal right?
Depends on the regulation agency and how they "share" the license, it's not necessary illegal.
Under the same license there can be different trading names/websites, if he registers as a trading name under the license and acts within the guideline, then he is not breaking any rule.
It's in a grey area, but as long as he doesn't break any rule then there's not much the agency can do.
I believe the best approach here is just to purchase gambling license rather than rent it. There's no real advantage of renting one but you will just create a headache. You will only go to the route of renting if you plan to get out early, so more than likely the OP is not after for long-term duration of business.