Question I wish to connect a G-Major / G-Major 2 to a combo amp that doesn't have an effects loop. Is this possible

You will need a pre amp between your guitar and the G-Major / G-Major 2. The G-Major / G-Major 2 will only accept line level signals, as opposed to an instrument level signal, that your guitar will provide (which will be too low for the G-Major and give you too much noise on the output).