Don't go to pay the Visa fee, once you get into Laos start a new application, submit, copy the generated QR payment code and go pay the fee. Just let the other application die on the order table.
And don't try and cheat the system by not being in the country.
Bring as much cash as you can in perfect new large denomination bills. Where's your actual driver's license, the IDP is useless without it, are you certified for scooters/motorcycles in the IDP?
Ensure your accommodation files a TM30 and report to local immigration where it has been filed with the TM30 and your passport when you have spent 90 consecutive days in Thailand