I need to take the ATP-CTP Course to be able to take the Knowledge Test. ATP-CTP does not include any kind of Practical Test, it only allows you to take the Written Test. Is that right?
Yes
After that I need to get the Practical Test done (Oral + actual flight in PA-44 or so, or a simulator session concurrently with a type rating)
Yes
I´ve been offered a Foreign A320 Upgrade/Conversion Course as a path to get the FAA ATPL concurrently with the A320 type rating. In that case, am I going to get the "Based on a foreign license" statement in the back of my pilot license? I want to avoid that. And I´ve seen that statement in a few FAA pilot licenses that made some kind of conversion from a foreign license, but without going through practical tests, only written tests and FSDO paper work and I believe you can only do that for PPL (See 61.75)
The ONLY certificate the FAA will issue based on a foreign license is a VFR only private. If the training doing the foreign upgrade class is a FAA approved 142 training center and if the foreign training course fills all the squares of the TC's FAA approved then they can issue a FAA ATP with the type rating. Otherwise it is
ISSUED ON THE BASIS OF AND VALID ONLY WHEN ACCOMPANIED BY [NAME OF COUNTRY] PILOT LICENSE NO. [NUMBER FROM FOREIGN PILOT LICENSE]. ALL LIMITATIONS AND RESTRICTIONS ON THE [NAME OF COUNTRY] PILOT LICENSE APPLY”
Sorry for shouting, the FAA guidance is in all caps.