Some clarifications. PayPal All-in-One Payment Solutions it's just a name for configuration section in Admin Panel and it combines three PayPal integrations:
- Payments Advanced - uses PayPal Payflow Pro payment gateway and provides a possibility to pay via credit/debit cards, Vault cards or PayPal Express Checkout (includes PayPal Credit)
- Payments Pro - uses PayPal Payflow Pro payment gateway and provides a possibility to pay via credit/debit cards, Vault cards or PayPal Express Checkout (includes PayPal Credit)
- Payments Standard - uses PayPal Express Checkout and has only a possibility to use Express Checkout or PayPal Credit
As you can see, the first two solutions just re-using Paflow Pro gateway and the last - PayPal Express Checkout.
So if you want to get an ability to use credit/debit cards and PayPal Express Checkout you can use Payflow Pro and you don't need to create three separate payment solutions.
Also, PayPal payment methods don't provide separate flow for debit or credit cards, so it doesn't make sense to separate them.
UPD: The documentation how to add a payment method on the Checkout step.