I am paying mortgage for all the rentals from business accounts.

Unless you have multiple units with a business account. 

This way, the operating LLC operates under the umbrella of the holding company LLC, resulting in two separate Secretary of State filing numbers.To proceed, you would open a second bank account under the name Holding Co LLC, doing business as Operating LLC.

That's what they strive for in normal business, taking on the normal risks.     

But now we are finally ready to start a family and need the space for our home businesses, in-laws, etc.

Check out Zen Business for forming an LLC it's pretty affordable and has a "pay as you go structure" They have a registered agent you can get as an upsell for instance.

If I do go the property management route - can i get a limited service option (say in which I find the tenant, collect rent, handle most maitnenance issues) and they primarily are liasoning with my vendors during US business hours and handle any urgent maintenance issues?

It's far easier to get repeat business from a prior customer than new business from a stranger.

Or when you want to scale your business, where you finally have a reliable experienced crew in place and you want to do more deals at a time. 

@Annwar Zahrieh There are certain transactional costs/ costs of doing business in Philadelphia to be mindful of, but I believe the fundamentals that exist in Philadelphia far outweigh this IF investing wisely.