What do you think of this investment portoflio allocation?

40% stocks. What kind of stocks? The economy is intertwined. There are economic cycle for different phase of development or seasonal cycles (like O&G, shipbuilding, consumer goods etc) which can fall between defensive or growth (and higher risk).
REITS are just 1 segment where you are like a landlord. Rising interest rates can be a concern for higher gearing REITS. Also rights issues, etc. REITS also have sectors from hospitality, industrial, commercial, residential.
Unit trust and Funds are similar like stocks but doing a basket, and could be region/country specific. You need to read the prospectus and what sectors they are investing in.

Too many questions, so sorry if I can't give you an answer.

Yes, there’s is diversification between different investment vehicles. But you didn’t specify the allocaction wise for each mode of investment. For moderate risk, I feel you should invest more on blue chip and consumer goods sector, a small minority on small-mid cap stocks.