Doesn't look like anyway is going to reply too quickly.
Any concerns about aluminium leaching are non-existent. Also any concern about air quality are non existent as I cannot see how air from a pump would be different as from a automatic machine.
There are a few other threads which should fill in your other concerns or email Ross at Portaspresso; he's a good bloke.
My friend has a Rossa HC and I have a PG. I prefer AirE as a name but whatever.
The reason why I like the AirE is because I don't need to hold it or use a stand during the heating phase and I think you're right, controlling the pressure profile is easier on the AirE, but others may disagree.
Once you have the technique sorted, they make pretty sweet coffee.