New LLC, how to account for $ spent before business bank account exists?

A new business involves several transactions before the business is officially registered, and before it has a business checking account. (For example, the state incoporation fees obviously can't be paid out of business funds. It also takes time to obtain the EIN that many banks require.) If these transactions are handled with an account in my personal name but which is never been used for personal expenses, is that sufficient to avoid the comingling of personal and business finances? Specifically, I opened a prepaid mastercard account and a paypal account, funded with personal funds. My personal address is on the account but with the LLC name added to it. My plan is to apply those funds to my capitalization of the LLC, but does anyone see problems with this? Would it be better to simply pay consider all this money to be personal funds and have the LLC reimburse me?

your cost to start up the LLC are deducted as an expense on the corps federal tax return form 1065 as 'other expenses"
(you'll have a statement showing other deductions that don't fit anywhere else and this goes in that statement)

Either way will work. Your first option is just fine. I don't see a problem.

I think it is fine to use your funds when you are starting. You will still have a record of receipts and/or checks and credit card payments.

It shouldn't take that long to get an EIN. I got mine instantly online. hmmm