It seems you are not Buying the Business Entity. You told us you formed a new Entity = the LLC, which as its own FEIN.
And unless you intend to submit paperwork to the IRS to be treated as an S Corp, there is no Payroll. Any payroll from the old entity is not yours, no matter what.
You need to separate your concept from "Absorb" to Transition. You set up for the new entity properly, using, for instance, the Tax form your new entity will file as the reference for the chart of accounts. Not the Old Company, but your New Company.
For this, "We will be purchasing virtually all of the assets of the business, including financial records."
You don't buy Records. You take on Assets, valued under the terms of the buy/sell. You agree to assume Liabilities. You address open AR and AP as part of this. But Not Payroll.
"My only question is how to export/import lists and data"
Their financial data is Not Yours. Yes, you can export the lists, such as Customer and vendor records, Items list.
Then you populate with Your Financial records, not theirs. Their data has nothing to do with how you are starting this business.
"but need some step-by-step instructions on the moving of the company asset records in QB to another company file?"
They are not Your Values. You just bought all of this, so your basis is New, and Now. Not their basis and not their depreciation.