The important thing is to keep the fund 'squeeky clean'...

The important thing is to keep the fund 'squeeky clean' regarding transactions, which means that you SHOULD NOT use personal funds to pay for shares or expenses or anything other than for contributions (making sure not to exceed limits as victorinc rightly points out), then use the fund bank account to pay for SPP, expenses etc. Anything else may be able to be explained by the Accountant / Administrators but can easily be a dance with danger and the ATO, plus incur extra admin costs.

Anyone tempted to pay for a SPP with part fund and part own proceeds SHOULD NOT be asking for guidance here but from someone qualified to give a qualified answer. Pay for it and get it right the first time. I know I bang on about this stuff here a bit, "but you know it makes sense".

FWIW, I suspect that for 2) - 3) above, if the fund is not segregated then an actuarial certificate would be required and that would determine the allocation of the total fund % split between pension and accumulation and therefore no pension pot and accumulation pot but a 'total fund pot'.

I therefore disagree with your part of your reply victorinc, (unless segregated, but that is not mentioned) but please DYOR.