I've had several bids for similar work in the past and pipe bursting seems to be a fairly expensive option.

You can hire someone to do all this and it will probably still be less expensive than LVP.

My current property manager doesn't instead sending a monthly ledger with the month's payments (company name, pay date, amount) as well as monthly income/expense statement.

See example below: DSCR < 1 Principal + Interest = $1,700  Taxes = $350 Insurance = $100 Association Dues = $50  Total PITIA = $2200  Rent = $2000  DSCR = Rent/PITIA = 2000/2200 = 0.91  Since the DSCR is 0.91, we know the expenses are greater than the income of the property. 

Obviously, newer homes are the "safest" bet because they will likely not need any major CapEx expenditure.What's the oldest property you would consider investing in for rental property before major systems (electrical, plumbing, etc.) become a major liability and expense?

Would it be a good idea to pay for the downpayment on a house that’s less than $100,000 and let my lender cover all the other expenses since I paid for the downpayment and I don’t have to pay them back, but I still have to pay the cost of the house and rehab, etc.?

An eviction by an attorney is probably not as expensive as you have heard when you consider only legal and attorney fees.

I do have the business start up expenses, plus the leases are under the LLC. 

The goal of a househack is to eliminate your housing expense as much as possible.

So the people who just bought expensive properties panicked and lowered their prices and they are competing with people that have owned their properties for years and have higher profit margins.