There are a few issues you haven’t considered.

I am assuming the owners of both properties is exactly the same? ie mum/dad own PPOR and mum/dad own investment?

Under the conveyancing act a property left to someone in a will takes the loan secured on that property unless specified otherwise in the will. (NSW, but probably similar other states).

This means if you are leaving the IP to one person and the PPOR to another the second person getting the PPOR will lose out because the loan for the property goes with it.

Tax deductibility depends on purpose and use the funds are put to. Security doesn’t matter. But deductibility will depend on how the loan is set up because if you borrow extra money and park it in a savings account before writing a cheque then this will destroy deductibility.

I don’t really see any other issues with using the PPOR as security for both. The loans wouldn’t be cross collateralised because only one property is being used as security. I myself would probably not do it this way, I would probably get a LOC on the PPOR and then borrow the deposit from this and the remainder from another lender. But if you don’t intend to buy any more properties then it may not be much of a issue.

I wouldn’t really worry about the bank holding too much in security. They are secured only up to a certain amount anyway. If you default they could repossess either property if both secured, but your way they could only repossess the PPOR straight away. But if you did default they would probably quickly obtain a judgment and that would allow them to apply to seize both properties.. Still, it is generally a good idea to give them as little security as possible

No CGT there, but you would pay it here on NZ property.
BTW I read a recent article regarding overseas purchasers of NZ property. Apparently 22% of all purchases are by Australians and 20% are by Chinese!

There is mutual recognition legislation in for lawyers, I would be be surprised to find that QLD solicitors could not act outside the state of QLD. They could act in NSW for instance. A NSW solicitor could also act for QLD clients. I have acted for a few interstate clients myself, but I don’t think any were from QLD though.

yes.

A trust is an arrangement in equity, where one person holds assets for another. This is the area of law that accountants cannot advise on – 1 because it is legal services and 2 before they wouldn’t have the knowledge.

Lawyers can also give tax advice, but you may want to run the tax side of things by your accountant too.

Sounds like you need a lawyer for the structures – this is legal work. No such thing as a 'correct' structure, only different structures, some of which may be better than others.

Going guarantor won't help with servicing – initially. You will still be considered to have the loan. But at least this allows you to remove the guarantee a few years down the track if your spouse is able to service the loan at that point on her own.

Consider the access of equity too.

No real easy way to answer, you need to speak to a broker and work out borrowing capacities based on the above scenarios and see how serviceability will be affected.

Consider also asset protection, succession on death (if in her name and you die…), stamp duty, further strategies..

Off the top of my head, there is a land tax threshold in QLD for trusts. Once you hit the threshold start a new trust and get a new threshold.
Vic is similar to NSW, if fixed unit trust then individuals get the threshold. There is no threshold, or very small for non fixed trusts. In Tassie I am not sure but one of my trusts was paying land tax – the amount was too small to force me to look at the relevant act to find out the rules.

Just clicked on that link and a security threat was detected – take care

The risk is that they damage the property or change it in a way that you don't like and then not settle. You may have to sue them only to find they have no assets. Make sure you get legal advice (from a lawyer!)

Right up RPI's area of practice.