assalaamu alaykum
My in laws are south african Cape malay! The community is very strong in Cape Town but spread through out South Africa. They have a body called the Muslim Judicial Council that have strong Islamic links in the communities. They have madrassas, Islamic schools as well as hifdh madrassas across Cape Town. My zawj's friend co-ordinates the hifdh project, he is Cape Malay and studied at Al-Azhar in Cairo. There are many inter marriages : Malay-Indian, Malay- Coloured (African/European), Malay-indigeneuos African (Zulu, Tswana, etc). As for moving away from Islamic values, i think that this happens to most people who move away from a living community of Muslims. However, from my perception as a South African Muslim, there are strong Islamic values among the South Africa Malay communities. Allahu Aalim.