I've used the search feature on this forum but didn't have much luck.Are there any US investors, hard money lenders, or groups that invest in flips outside of the United States, specifically in Europe (Netherlands, Spain, etc.)?

You will need money to put down on the property.  

I wanted a house for myself to live in and I had been living with parents for two years to save money.

We have been able to save up some money for our first turnkey multiple unit building.

Spending the owner's money, not saying anything, and letting them discover it while reviewing the monthly statement is unprofessional.

This risk is amplified the less money you have attached to the deal.

The expert you are looking for is called a Land Surveyor, they're going to want 5k-15k, if you want to make any money on your project you need to build a house so you also need an architect, they will want 10k-50k, if you're in a hillside zone you will also need a geologist, they're going to want 10k, you will also need a biologist, they're going to want 2k-5k.

But now I'm thinking of renting the whole house and getting a cheap apartment to save even more money.

They are worth the money for a good hot tub that is mentioned all the time in reviews and doesn't have a ton of issues.

@Malcolm Brown it is great that you are thinking of the money to fund the deals you are going to get started with but understanding what a deal is, I think, should be the starting point.