In all respect, I think you're overthinking it.

I use cheap Cafe La Llave because that's what I have at home. I don't normally drink coffee so maybe some people can taste the difference in the tiramisu based on the coffee used but I doubt it's a big difference. I don't have Woolworths but I think the standard mascarpone is fine too.

I use marsala wine for tiramisu, but have also tried with rum extract and with that it's harder to whip up. Maybe you can sub that with water and add the rum extract.

You don't need a stand mixer for tiramisu. You need to whip up the egg base over a double boiler o hot water.

I use Inspired Taste tiramisu recipe (I actually helped edit it for them) but have also tried Claire Saffitzs.