I self manage currently use Rentredi for management and REI Hub for Bookkeeping.

It also doesn't make things harder for bookkeeping/accounting/taxes which is good as well. 

Your property management company will at least have the expenses of creating the company (I would strongly recommend creating an entity), bookkeeping, tax preparation and the 401k plan setup and management fees.

Before someone says you'll pierce the veil, you will that's why you need to make sure you're well capitalized and keep bookkeeping separate.

If you are looking for bookkeeping software I'd be glad to show you you what I have built.

Lately we are considering hiring my two kids, who are under 18 years old, for some office work, such as setting up a rental website, mowing lawn, bookkeeping, etc.

My Bookkeeping is $65-$70/hour and but cost $1,000 to make it operational.

You need that level of clarity and bookkeeping if you are operating in both the investment entity as well as the construction entity simultaneously.   

If you're referring to Airbnb/VRBO insurance for damages then I would say the clear answer is "no" but you can purchase a variety of products to lower your risk.For bookkeeping, doing it yourself or hiring a bookkeeper would both make sense.STRs will have all of the expenses that an LTR would have plus a bunch more like toiletries for example. 

My name is Aya and I'm excited to dive into the world of real estate and property management.As a newcomer, I'm eager to learn from experienced mentors, real estate agents, lenders, contractors/handymen, bookkeepers, CPAs, lawyers, insurance agents, and property managers.