Not read all of this yet but just wanted to respond to one of your points Starlight, re vaccinations being safe at 2 months but not at 1 month - it's actually not because of safety but because of response to the vaccination.
When babies are born they are not able to produce their own antibodies. Over the first few months of life they develop the ability to produce antibodies. However, in the first couple of months of life they have antibodies from the mum and if the mum breastfeeds they will continue to get some antibodies this way too.
Vaccinations work by injecting a small amount of either a killed verson of the bug vaccinating against, or a bit of the bug's genetic material, into the body, he body produces antibodies against that and when the person next encounters that bug the antibodies are able to fight the bug so they don't get the infection (I'm using the highly technical term 'bug' to cover bacteria and viruses). This is exactly what they body does in response to getting the actual infection but with the immunisation you don't get sick because the bug has been either killed or broken down. You may get a fever and aches and pains as this is the body recognising the bug as a pathogen and mounting an immune response. This immune response needs to happen or the immunisation won't work.
Very young babies less than a month of age produce such a small amount of antibodies if any that there is no point giving them an immunisation - the body can't mount an immune response. However they are still protected by the mum's antibodies. As they get a bit older the protection from the mum is wearing off and their ability to produce antibodies is kicking in a bit so we immunise them against things that kill babies such as H. influenzae (causes horrible horrible meningitis that is very often fatal and throat infections that can cause the upper airway to close completely leading to death by suffocation), pneumococcus and men. c (which also both cause fatal/disabling meningitis), whooping cough (which is just highly unpleasant in bigger people but fatal in some babies and incredibly difficult if not impossible to treat in the litle ones who get very sick).
However, their antibody production is still not great which is why they need boosters (wheras if you have an older child who is unimmunised they may just need one vaccination as they have much better antibody production).
So it's not a case of these vaccinations being unsafe for tiny babies, just that they won't work and they are less necessary as they still have mum's protection (hence the drive to immunise pregnant ladies against whooping cough - it's so the baby gets the antibodies through the placenta so is protected in the first month of life where it is most risky to get it (as the babies I have looked after who've died from whooping cough have caught it when they were too young for the vaccination)
As for the volume being injected being the same in everyone - it is because a very very tiny amount of the material is needed to mount an immune response and that doesnt vary by size of the person - all it needs is one or two bits of bug to come into contact with one or two white cells and that's enough - (with norovirus you can become infected by coming into contact with just 2 viruses!). These volumes have been studied carefully - immunised populations have been tested following immunisation to find the minimal amount required to cause immunity in the majority of people. Most of what's injected is actually water or saline and the volume chosen will be enough to ensure the vaccination is fully dissolved and also to be big enough that you don't lose half of it in the hub of the needle (generally if I'm injecting something that is less than a quarter of a ml or so I'll dilute it just cause it makes it easier to measure and inject)