Hi Laura,
My name is Thessa and I am a Consultant at Asiaxpat domestic helper employment agency.
You are correct that domestic helpers nowadays are not being mandated to exit HK due to the pandemic and HK Immigration understands the situation therefore helpers just needs to report to the HK Immigration to inform them that he/she is unable to exit and they must defer their home leave.
previous employer must pay the helper's air ticket (usually in cash as helpers are unable to exit) since the employer is leaving HK, they must pay all settlement of fees upon termination of contract and you as the new employer must provide 1 round trip ticket to the helper within the 2 years new contract.
normally, helpers stay in a boarding house while they wait for their new visa with the new employer and they pay for their own accommodation and food.
if you have further inquiries or need help in processing the helper's working Visa and employment contract, please feel free to call or whatsapp me at 9311-5905 and I am happy to help you.