Challenge on a BPO role is that the majority of roles are not well paid unless there are languague skills required and also a lot of BPO orgs have offshored the bulk of those roles due to high (relative) salary costs in Ireland. Hence, unless you have a specialist niche, you are recruiting for minimum wage roles or minimum wage + a small %.
Most of these companies are also multinationals and have their own global recruitment teams. Accommodation is certainly an issue, less so outside of Dublin but still a problem. It's fine for those in senior or high end tech roles, they'll find a place or their employers will pay hotel cost for a couple of months until they settle but not for lower end roles.
I've never known a firm to pay for referals or prospects. Normally, it's pay per hire and for low end BPO jobs, 15-20% would be the absolute max (+ VAT) for an actual hire, normally I'd pay after 3 months and would seek a free replacement or a rebate if the candidate did not work out or left the job. I'd also expect any agency to deal with the heavy lifting if visa's are required and for pre-employment screening.
Note if your employer finds out that you are potentially involved in the hiring of staff by their competitors, chances are they will take disciplinary action.