Short Answer
Essentially all your unsecured debts can and should be included but some will survive and not be written off in the process.
A Bit More Detail
You can not pick and choose which debts to include. You can’t include all of your credit cards but decide not to include your brother and pay him outside the proposal. If out of goodwill you choose to pay your brother further outside of the proposal that is up to you, but during the proposal your brother is treated the same as any other creditor.
Taxes, cell phones, utilities, lines of credit, credit cards, mortgage shortfalls, car deficiencies, anything unsecured can and must be included.
Secured debts must be recorded but if you want to keep the item that is secured, you must continue to make the payment on that item. Car, house, boat, motorbike, trailer etc. If you are upside down on the loan (you owe much more than it is worth) this is the ideal time to forfeit the item and walk away from the outstanding balance.
Fines will survive and need to be paid before driving privileges are reinstated.
Maintenance and child support can be included but will survive and will need to be paid in full.
Student Finance debt will survive if you have been out of school less than 7 years but during the proposal you are protected from collection proceedings. Interest continues to accrue and should be paid during the proposal.
These three types of debt are included in a proposal and they will receive their pro-rata share of any payments, but their balances will survive whereas other balances do not.