Miss conduct - That would completely depend on their immigration status/ the visa they have come on.
Basically, if they have made an asylum claim, ( e.g. travelled to the U.K and requested to seek assylum on arrival), then they are not allowed to work or claim mainstream benefits whilst their assylum claim is processed. Whilst the government is assessing their claim, they will be given very basic assylum accomodation, ( I've seen it and it's grim tbh), and approx. £30.00 per week per person in the household. They can access the NHS and state schools for children, (if needed), whilst the claim is being decided. They are also entitled to free school meals for there school age children whilst the claim is being decided. The family will never be allocated a "council property," during this time; if they need accommodation they are given specialist assylum accomodation which is normally very run down.
If they are granted refugee status; they will then be able to access the same benefits as you or I, ( e.g., if they are looking for work they could claim Universal Credit, if they are caring for a disabled person they could claim Carer's Allowance etc). So in theory; if they were granted refugee status eight months after arrival; they would be able to access mainstream benefits eight months after arrival.
Most immigrants obviously don't come via the assylum/ refugee route however.
Most non-european immigrants will need a visa to travel here initially, ( e.g. a student visa/ work visa/ spousal visa) . The conditions on nearly all of these visas state the immigrant is not allowed to claim public funds; therefore anybody here on e.g. a student visa would be blocked from claiming Universal Credit/ Housing benefit etc. The DWP are stringent about checking visas before a benefit is paid out; so they simply wouldn't be able to complete the claim. Additionally, even attempting to make a benefits claim when on a no recourse to public funds visa could, ( and often does), lead to the visa being revoked.
In certain circumstances; after five years some non-european immigrants who wish to stay in the U.K permanently may be able to apply for indefinite leave to remain from the Home Office, ( lots of other conditions are attached). If after five years on a work visa; an immigrant was granted indefinite leave to remain and sent the appropriate biometric cards to verify this they would then normally be able to claim the same benefits that you or I could.
Then you have European/ E.U nationals; who are obviously allowed to come and live in the UK without a visa/ claiming assylum.
Under nearly all circumstances; they cannot claim any benefits without working in the U.K first, ( there are a few minimal exceptions, such as if they are closely related to another EU national who is working in the U.K).
If they are engaged in "genuine and effective," work, ( normally measured by the fact they are paying NI), they can claim in-work benefits, ( e.g. Universal nCredit).
They can also claim if income related benefits if they are self-employed, ( providing it is genuine/real/effective self-employment)
If they lose their job through no fault of their own; they can claim out of work benefits for six months before the DWP looks at whether to close the claim.
They can claim disability benefits; but need to prove they have worked first and have had to stop working due to ill health..they are not able/not allowed to just get off the plane and claim either disability or unemployment benefits.
And as of very recently; after five years residence e.u nationals can claim settled status in the UK . After that; they can claim pretty much the same as you or I.
The exception is PIP or Attendance Allowance; even if you are working, you cannot claim these until you have lived in the U.K for 2/3 years. The only exception is if a doctor can certify you are terminally ill and are expected to live less than six months.
Unfortunately, these rules can cause a lot of people to experience destitution. I have dealt with many EU nationals in particular who have no entitlement to benefits or support in their home country; and have found they have no entitlement to support in the U.K either.
We regularly recurve calls from people who have come here on a work visa, got very ill and needed to stop working, ( stroke, cancer, hear attack etc). and found themselves destitute as they do not have money to survive.