From a tax perspective, fix n flips will put you in the ordinary income category.

This is known as depreciation recapture and is taxed at a rate equal to your ordinary income tax bracket up to a maximum of 25%. 

In THAT case:- you don't have to have an LLC- you can use Section 179 if the vehicle is 100% business and is the qualified kind of vehicle, i.e. not a passenger car- in 5 years, the entire sales price would be taxed as ordinary income, and you can call it depreciation recaptureHowever, you mentioned that this is a rental business which opens a lot more issues to consider:- you need to be able to say with a straight face that you needed a new truck in order to manage your rentals- you need to track business v. personal use- Section 179 may be limited, depending on your overall situation, and you may be better off with the 100% bonus depreciation- your overall losses from the rental may be limited, so deducting an auto might not make a difference even if otherwise possible

My accountant stated, “The losses incurred on the rental properties cannot be taken and will be carried forward as your income exceeds $150k, thus no losses can be taken against your ordinary W2 income.”I was really surprised by this.

This is why I recommend you market through ordinary channels for anyone looking for a long-term rental.

I will suggest something that is out of the ordinary but works for my parents.

It's just an ordinary bank account where you hold funds on behalf of another and it's separate from your funds.

Quote from @Joseph Palmiero: Yes, you need to claim the rents received as income and claim the rents paid as expenses.And assuming the rent expense is ordinary and necessary and directly related to the business. 

"ordinary and necessary" for the production of rental income and 2. for a reasonable amount.I think the case for both of these should be easy to make.We are on good terms with the tenant and expect to obtain a Buyout Agreement before the year end.

Even if you have one entity, the income from rental will still be passive and income from Flips will still be an ordinary income.