MDGC 7 UI concept

Hello Experts,

I have already come accross many definitions regarding MDG Customer UIs. I would like to understand what the difference is between

1. customer UI vs ERP customer UI
2. customer UI vs customer like UI
3. lean customer UI?

For the 2. point - all I know that customer UI is similar to the bp transaction, and customer like UI is similar to the xd* transactions (so in the first case BP partner is created originally, and if configured, customer too; but in the second case only customer data is created). Both CR type CUST1P1 or CUSTL1P1 type are included here?

I've already searched many places, but could you please help me what is the essential difference/relation between the above definitions?

Kind regards,

Tamas