I think in your examples you should ask the business type question (i.e. is point-in-time recovery needed - but in business speak) but not the others which are technical and should be figured out later once the business needs are clear.
Managers may well then ask how much more PIT recovery would cost. On investigation you will probabably find it is not that much more expensive nowadays.
Also as well as the other very good answers already:
How long should long term backups be kept? For example in your country there might be a law that financial data be kept for a certain number of years. Or conversely there could be a law that transitory personal data be deleted after a certain number of years. This should be in the SLA mentioned by Tom.
If you are required to take very long term backups you also need to consider how to get the information back again if the metadata (sorry I do not know MS SQL so not sure if it is called a schema there) has changed in the meantime. Therefore you may want to long term back up the schema or perhaps take occasional exports as well as backups.
Get a disaster recover exercise put in the plan at an early stage otherwise management may not include it in the budget. You may find you need both onsite backups (for quick recovery as in most cases it will not be a complete disaster) and offsite (for disaster recovery in case the whole site is unavailable).