I talked︀ to HSBC. The minimum deposit requirement is only fulfilled as long as you hold the︁ money within the Expat/Premier account. That account offers also investments, but own stock trading is︂ not possible. Automatically, position transfer is not available. It is simply not a broker account.︃ You can only choose by a range of investment products HSBC offers. Further information and︄ details can't be given by the hotline, because they simply don't know (I believe them).︅ Once the account is opened and the Relationship Manager had been assigned, more information might︆ be available, but not in advanced.
I hope this helps someone. I am still not︇ sure yet if I want to go that way. The offered investment products within the︈ Expat Account are probably quiet expensive and inflexible. I prefer to be my own investment︉ manager and choose stocks / ETF by myself. But maybe it's worth it for the︊ advantages I get to let HSBC manage 75 k of my wealth.
By the way:︋ I also talked to Barclays, and for them I received more or less the same︌ answer.