You need to allocate the cost to the Building and the equipment. The building will be depreciated over 39 years(being commercial) and the equipment will be depreciated over 5 years. You do not have to track the equipment rental income separately from the lease income.
If you sell the equipment than depending on the adjusted basis of the building, you may have a gain or loss on such sale.
Let me know if you have any question.
Please note: This advice is provided with the understanding that all the relevant facts have been provided by you. Any change in facts might affect the advice given and hence may not be relied on in such cases. Nothing contained in this reply was intended or written to be used, can be used by any taxpayer, or may be relied upon or used by any taxpayer for the purposes of avoiding penalties that may be imposed on the taxpayer under the Internal Revenue Code of 1986, as amended.
You do not need to list each piece separately. You can record the entire equipments assets with class life 5 years together.
Yes, you will reduce the value of the building with the equipment cost since part of the cost will be allocated to equipment.
You may use Form 3115 to report the depreciation that you have not claimed from 2005 through current year in the current year.
Link to Form 3115
You would split the equipment that is sold and report that separately in the year you sell it. Other equipments can still be grouped together.
Let me know if you need help with the 1031exchange related question you had posted earlier...