if she buys a house first then uses the equity to build 4 units, then she can rent out all 4.
She can then claim the major depreciation benefiots of the newly built units and interest which would be far better than only being able to claim on 3 units, not the one she lives in.
She may not require a guarantoor for the house so you could become guarantoor for the units instead.
Also might be best no to live in th same unit block you own for various reasons.
