I have had some wonderful relief from using the suggested regeme for my rheumatoid arthritis (andrographis & holy basil, chapparal and pau d arco for bacteria then spanish bee pollen and vit c high dose for adrenals).
This relief is in the form of a horribly swollen knee reducing faster than ever before, compared to anti inflammatories and 'usual flare up periods'.
I want to thank this forum for pointing me in this direction.

Glad to hear you are doing better.

I have three questions about this -

1. How does one get these bacteria invading in the 1st place (via unclean foods, general stress related lower immunity etc)?

There are several bacteria implicated in RA including a form of chlamydia and mycoplasmas. So they would have different routes of entrance. Although the weak adrenal component does suppress the immune system allowing the bacteria a better chance of taking hold.

2. Can these bacteria evolve to become immune to these herbs? 

There is always that possibility. But that it why I recommend the herbal combination. This hits the bacteria harder and from more directions so they are less likely to develop a resistance. For example let's say that the bacteria is building up a tolerance to herb "A". But the survivors that are building a tolerance to herb "A" are still being nailed by herbs "B" and "C". So the chances of them surviving the various herbal antibiotics is pretty slim.

3. How long does the bacterial and adrenal treatment need to last (until swelling subsides or indefinitely etc)?

That depends on many factors such as how suppressed the adrenals are, if the person is adversely affecting the adrenals with stimulants or steroids, how much stress the person is under, etc. But the bacteria can be killed and the adrenals rebuilt to eliminate the problem.