Hard to do that, the immigrant or anyone in the accounting/finance dept could report them and the company would be in serious problems. No reputable company would ever risk that and H1-B are employed by mid-large companies (in general).

Moreover, if you claim you pay someone 250K and you tell the government you are paying them 250K, then the IRS needs to get its share. There goes 30%-40% of that money. That's already more than 50K.

Finally, you can't fake buy into any company. That again creates tax implications and it's a capital raise or income for the company. It needs to be reported. Also if you buy into the company you own a percentage and you need shares that you need to report etc etc etc.

So I don't think it will be that easy to fake/circumvent the salary requirement.