Hi Hesham,
Thank you for the precisions.
In BAMM no.42 there is a short article about the LACAB T.7. It includes an extract from La Conquête de l'Air July 1933, describing the foundation of LACAB in 1933, and giving the names of the administrators: baron Baltia, M. Jean de Steenhault de Waerbeek, M. Jean Bastin, M. Fernand du Roy de Bliquy, with Henri Delhove as commissaire. The Nagelmaekers bank and M. Bastin together owned 90 percent of the LACAB shares. You see that none of these names appears in the source about ACAZ and Zacco.
The main designer of the T.7 was Robert Servais (and Guldentops), who was apparently not linked to ACAZ / Zacco. Despite the name similarity, I don't think there is a compelling reason to believe that ACAZ and LACAB were directly related.
Of course the world of Belgian aeronautical construction was small, so some people might have been involved in both companies. For example René Bulté is known to have worked at Zacco before 1928 and at LACAB after 1934, but this does not mean much in my opinion.
Adrien