Hello, can anybody please help me. I am interested in doing macro photography and would like to attach my Panasonic 45-200mm and my Panny 20mm 1.7f to my GF1 in order to create a macro lens. What will I need for step-up/down and reverse rings to do this?
In order to reverse mount your 20 to the 45-200, you'll want a couple of adapter rings and a reversing ring in between that has a male-male thread. You'll want to set the aperture on your 20 first on the body, then detach the lens while still powered to lock that aperture in place. The downside of doing all that is you'll end up losing some of the excellent IQ of your 20 by feeding it through the 45-200, which isn't as good of a lens.
An alternative is to buy a reversing adapter for your 20 and attach it directly to the GF1 body. It would give you a much more compact setup and still end up with about 1.4:1 magnification. If you want more magnification, you can add some m4/3 extension tubes.
A third alternative would be to buy a close-up lens like the Raynox DCR-250 and put it directly on your 45-200.
A fourth alternative would be to buy a cheap dedicated macro lens and adapt it to your GF2 with the appropriate adapter.
Also can you please advise as to what type of twin flash I can use for my lenses?
No need to use fancy twin flash units. Any on- or off-camera flash, preferably with a diffuser, will work fine. You can use it either in manual mode or spend a lot more money and get a TTL flash you can use with the chord. Try spending some time on the Strobist website to get some tips on lighting. You can also buy some cheap LED light rings off eBay to add light.
Last question, do I need an EVF to do macro work?
Nothing magical about the EVF other than it provides more stability by virtue of forcing you to be attached to the camera as you look through it. An EVF will allow you to take shots at slightly lower shutter speeds than looking through the LCD. You can find other ways to achieve stability such as using a tripod, monopod, or any nearby support like a walking stick. Bodies like the G and GH series are a bit better at field macro shots for that reason, but plenty of people take great macro shots with their GFs. It's just not its strength.
Hope this helps. Good luck!