I my perfect world this is what I'd expect from an au pair and what a family should expect from an au pair. I speak as a ex nanny, now maternity nurse with 15 years experience of living in my work house. Its not easy but it can be very workable with common sense from both sides.
I wish we could do away with the name "au pair" and maybe use "live in home help". Could be "parent help" as well. This would clear up "rules" when in fact in the UK there are no rules on au pairs unless for A2 nationals. It means that the families would be employers and the home help employees. This means they will be covered by laws and as such everyone will have a clear contract that is fair and pay taxes (if needed).
I also think there needs to be a clear understanding of pay while living in. There needs to be a clearer understanding of minimum wage while living in, I do understand there is no minimum wage for live ins but maybe this needs to be stopped. There are some horrific jobs advertised where employers expect 60 hours a week for £70. This is not fair! As there is no official au pair visa anymore then "home help" can work what ever hours are agreed upon however the pay MUST reflect this.
Also as there is no official rules "home help" can work with any ages and unsupervised however it is the employers responsibility to ensure the employee understands safety aspects of child care. The employer should make sure the employee has a first aid cert and I think offer to pay for it if the employee stays the contracted time.
At advertising stage the employer needs to state: area of country, living accom, about employer and family; pay; hours to be worked and what is to be included in those hours.
At interview stage the employer needs to make sure that the "home help" understands that they will be treated as an employee and will be covered by the laws of the country which means they will be treated fairly. I'd also expect a contract to be be drawn up before au pair starts and it to be signed on first day of job.
As a young person (mostly likely) new to the country and maybe homesick and overwhelmed it would help if the employer would have an easy few weeks with acclimatising employee. When the employee arrives there should be a hand book of local activities, a map of the area pointing out where things are, even a gift basket of local products or toiletries. The employer should make the employee feel at home, for the time they are working it is their house too.
As for duties: most of these home helps will have no formal training in child care and as such you can expect them to be more of a baby sitter eg reading stories, heating meals, supervising but unless otherwise stated they will not organise activities themselves until both sides are comfortable.
For cleaning I truly believe that the home help only do light house keeping duties. Eg wiping counters, empty dishwasher, hoover most used parts of the house, wiping sinks (but not toilets unless its theirs only), maybe mopping if meals are mess, folding washing (not ironing). They are not cleaners and will have being bought up with different standards (maybe best to ask at interview stage whether they like to clean?). If employer wants cleaning then they need to contract a cleaner or find a home help that they pay better to do more in depth cleaning. The employer should draw up a list of what is expected to be done each day (or AM/PM), the first week the employer should work alongside the employee to ensure they know what is expected. The next week the employer should let employee get on with it and daily comment on what has being done well and what needs to be worked on (do a shit sandwich makes it nicer for everyone). Now hopefully if the work is fair and the employer has chosen the right employee then there should be no issues. However it is the employers responsibility to continue to ensure the employee is doing the job asked to a reasonable standard. Have a weekly/monthly meeting, do an evaluation form if needed. Thank your employee for any work done especially if they've gone above whats needed. If they are not doing the job adequately give a verbal then verbal warning and if needed get the to leave. It will not work if the employer is feeling frustrated. It will not work if the employee is not doing the job. But it can work with good communication on both sides.
I'm in the process of writing a book about working with household staff especially live ins. It can be a very difficult job as every employer has different standards and its hard not having an "off" time. I've had some great experiences over the years and can say that the best ones have treated me like a human and if I've needed to improve on anything they've said it constructively and in return I've gone over an above my duties. There is also got to be a little give and take from both sides. It is a very fine balancing act.