Nice pics!
Never seen a Spotted Grass Frog with that intense bright green colouration before, although close to. The bluey has nice markings as well.
Who cares what your voice sounds like, it isnt that bad, have heard alot worse, and as stated above alot of people dont like hearing their own voice. Your voice will change in the next few years anyway.
You were correct in your id with Lampropholis guichenoti, they do vary a bit from pop. to pop. up the east coast, and in a recent paper i read that the northern and southern populations are genetically distinct and may prove to be 2 species, see what happens with that one.
Niveoscincus metallicus are localised around Melbourne, from the coastal area of Port Phillip like Ocean Grove, Geelong and a little north, from areas of the Mornington Peninsula and the Yarra Valley beyond Lilydale and from Monbulk, Emerald and Gembrook areas and beyond.