Financing

It depends on the loan.  FHA can be as low as 3.5% (if you qualify).  Conventional can be low too, but your rate / PMI / payment change with the size of your down payment.

Your rate is priced off market rates plus your risk profile: credit, down payment, loan type, occupancy and debt to income ratio.  There are so many variables.  The advertised rate you see online is rarely the rate you get. 

Definitely expect pay stubs, W2’s / 1099’s, tax return (often), bank statements, identification and written explanations for large deposits.  Self-employed borrowers most likely will need more paperwork and more scrutiny.

There is no single number.  Higher credit usually means a better interest rate and easier approval.  If your score is borderline, your rate, PMI and approval odds can change more than you think.  A mortgage professional can help you determine whether they can make your existing score work or it makes sense to work on repairing your credit.

Yes. Looking before getting pre-approved wastes time and creates bad assumptions. Pre-approval helps you shop with real numbers instead of guesses.