lf you really want to call yourself a business and pay SE taxes on what should be passive income then have at it ... if you are ever audited then you can have this discussion with them.
Now if your real goal is to get SS benefit credits by putting this income on the Sch C then you have another option. The rental business can HIRE your separate Sch C business and deduct the money they pay you (and issue a 1099 to that separate Sch C business) on the Sch E and the income & expenses to complete this work could be reported on the Sch C.
