I understand your questions/concerns, however, they aren't valid or realistic, let me explain why...
1. tenants don't call for backed up shitters, they plunge them, just like a homeowner does. if the problem is serious enough for a plumber, after the tenant calls you, you call the plumber.
2. dead beats don not hire attorneys, they are broke. the eviction process actually is very simple, it takes 30 days and and costs about 80 bucks, unless you need a sheriff (additional 50-60 bucks) if you have to go the full distance. However, experience in this issue, tells the story like this,
"deadbeats move before a sheriff ever gets involved" deadbeat tenants do not want the sheriff nosing through their lives while my moving crew moves their belongings out to the curb, while they watch from the public street because they are no longer allowed on the property. the tenant will be gone before this ever happens 9 out of ten times. key to this is: check a person out, verify good employment history and check with local court house for recent evictions. These are the very effective screening methods, both are free and easy to do. requiring a matching deposits get rid of the broke guy also. Never rent to anyone, who says "can I move in today?" lol.
The eviction process is technically simple here in GA but I asked my very sharp attorney about this just last month and he said if they hire an attorney they can literally squat rent free 6-9 months while its wrapped up in the courts. Yes, attorneys cost money, but said jackass could have a cousin who happens to be one. My attorney and his legal secretary emphatically said don't get into rental houses.
3. roof replacement is paid for by insurance, roofing companies pay your deductible out of the claim every time.
You are assuming that you're lucky enough to have hail damage.
4. HVAC systems,have them maintenance by a A/C service company every year. they run very efficiently this way. If you need to change them, you just pay for it fro your profit, "cost of doing business" I very rarely do any work myself, case and point, I only do small projects, that my kids can do with me (daughter-8 & son-10) so they can earn some money and understand the value behind money. "you work for your cash, no allowances"
5. There are risks in everything we do, real estate is not exempt from this. I can tell you this from experience, buy your properties right, screen your potential tenants, you'll have more free time on your hands than you know what to do with.