Im in the process of finding a permit to move to suisse, from uk, so trying to get roughly the same info but,
From what I've seen you can all come over on a 3 month tourist visa (no actual visa needed) and apply for your permit during that time,(you can work during this time, and your company can apply to send you out here for work) obviously the sooner the better.
As to the permit, it will probably be a B but the canton that you move to actually decides. If your moving to lausanne it will be Vaud.
As your from an EU country it should take longer than 3 weeks if accepted (very unlikely you'll be declined)
Has your wife got work lined up? if so process would be same for her, but if not she can arrive on a 3 months tourist visa and then find work and ask them to apply, or apply for a residents permit which allows her to live here, and i think gives her 12 months to find work (but she wont be sent back to Ireland after that, just have to apply again
As i say, im also still trying to get info, so this may not be 100% accurate
Also will be moving to close Lausanne