If your logbook has all of the key elements it really doesn't matter where you got it from A lot of engineers copy the CAA CAP 741 Engineer's logbook into WORD and keep their notes that way.
The challenge with your logbook will be getting it signed off. The expectation is that you will have worked in an EASA approved PART-145 organisation and your experience will be claimed in that environment.
As for your certificate, it really does depend on what the certificate is. If it is merely a certificate of learning then it will have no value in the license application process. If the certificate is a course completion certificate of attendance on an EASA approved licensing course where you have completed a course of learning and examination then the validity will be laid down in the regulations as highlighted by the post above.