Question about Tamiya Plastic glue

No, unfortunately not, from my own experience plastic glue only makes Lego parts slimy but does not create a real "weld". The parts only stick superficially at most. This glue is specifically made for modelling kits (e.g. Warhammer etc.) where it works best. It works reasonably well with acrylic glass but not with PVC.

I really can't tell you, I haven't glued any Lego bricks with it, but I can well imagine that the Lego bricks are also made of plastic, so why shouldn't it work?