Pardon my terminology. I'm very much not a lawyer, but I used to watch Ally McBeal as a kid, so I think I got the hang of this.
This is actually a subset of a vastly larger problem, so the arrangements may seem a bit weird. This is an EU question, but having any common law jurisdiction answers would certainly help, as would anything even tangential on this.
We have the following legal entities:
Main company X, located in either Ireland or Northern Ireland (UK)
Accounting company Y, located somewhere in EU, could be the same country as X if that makes things easier.
Freelancer A (and others), located somewhere in EU, ideally the globe.
X has made a contract for service with A. X wants to lower the bureaucracy overhead for A, as it is essential for the business model for make it easy to join as a freelancer (think Uber). Ideally this would be as hassle free for A as having a contract of service with X.
For this, X has two different models:
1) A sends X all the necessary paperwork. When A gets paid, X pays income taxes, pension payments, VAT and whatnot for A and sends the rest for A.
2) A sends Y the paperwork, X sends Y the full amount payable to A and the info required, Y pays the taxes etc and sends the rest to A.
Are either of these (or modifications of those) possible without the relevant authorities interpreting this as a contract of service instead of as a contract for service as intended.
It is worth noting, that even without X handling tax bureaucracy for A, it is not completely clear if the model would pass as a contract for service. Based on the IRS 20 questions on the subject 15 or so say it's for, 3 are indecisive and 2 say of. It would also not make any sense for X and A to have a contract of service relation (again, think Uber).
EDIT:
A few things to clarify:
Our goal is not (necessarily) to minimize taxes for A, but to minimize bureaucracy overhead for working small sporadic gigs for the company
Scope of A's work could range from anywhere from an hour to a few years
Ideally A would just have to provide X (or Y) the required paperwork, then receive payments as if he would be an employee and not have to worry about taxes or social payments.
Having an employer-employee relationship between Y and A is almost as bad as having it between X and A
The main reason why we want to avoid employer-employee relationship is not tax optimization or avoiding social payments, but avoiding minimum wage regulations. This may seem quite exploitative, so I might need to open up the idea a bit more:
The point of company X is essentially to provide a legal & software (latter one being our core competence and first one just a major obstacle) platform for collaboration between the mentioned 'independent contractors'.
As a simplified example that wont catch many of the reasons why we need a legal platform as well:
Freelancers A and B collaborate together to build the ultimate fart app. A handles the coding and clocks in 100h while B farts on mic for 50 hours, both work being deemed equally valuable. When the project cashes in, A will get 2/3 of the profits and B 1/3. A and B can also sell their equity to 3rd parties any time they want.
This would be implemented by having a (quite exotic) contract for service between company X and independent contractors A and B.
Now consider the two following scenarios:
The app ends up grossing very little or nothing at all, meaning that hourly rate for A and B would be way below minimum wage. This would obviously mean a disaster for company X if the authorities interpreted the relationship as employer-employee, so that is why we absolutely need to steer clear of it.
Freelancer C joins the project and does 10 hours of design work. Let's say that C his main source of income from a steady 9-5 elsewhere and does not really do freelancing other than this gig. While setting up a service company for A and B would possibly be an option (given that this is not their only collaboration under company X), the overhead for C would be completely unbearable.