Some Panny G5 and other micro 4/3s question

A few questions from someone who is seriously considering joining the micro 4/3s party

1.  There are 3 Oly and 1 Panasonic 4/3 to micro 4/3 adaptors all of which seem disproportionally expensive.  There are also clones such as this one http://www.ebay.co.uk/itm/Four-Thirds-to-Micro-Four-Thirds-Adapter-f-Olympus-Panasonic-Micro-4-3-M43-MMF-1-/110907597426?pt=UK_Photography_CameraLenses_Lens_caps_hoods_adaptors_ET&hash=item19d29ba272

for much less outlay.

Why do we need 4 proprietary versions? Is there a performance difference?  What is the drawback of a clone after all surely it either works or it doesn’t.

2..If I use my Samyang 8mm FE with a G5 does it give me the same field of view as it did on 4/3s?  Does the spacing distance of an adaptor make any difference to the view that any lens sees.

3.  I take a lot of pictures like this with my 70-300 on my EXXXs.  .

Can I achieve similar results with the Panny 100-300

4.  If I like the 100-300 is there anything I am likely to miss if I throw away my 70-300?

5. If it is difficult tracking moving objects with an EVF as most experts say (I tend to disagree having used an FZ50 quite successfully for several years) how is micro 4/3s such a good platform for video.

6.  Apart from the IS loss, am I likely to have any issues using my Oly 35mm macro on a G5?

7.  And finally the 64000 dollar question.  I take a lot of BIFS and I know that the purists will say this is definitely not the way to do it but I don’t do badly with the E620and 70-300 and 40-150 and to be quite honest the former is a pain in the a**e.  When people say it won’t do BIFs do they mean it won’t do BIFs and I really need a Canon EOS5 and a very expensive 400L  lens (I know money and weight are the BIF answer) or do they mean forget it even if my main tool is an Oly 70-300  because I will be disappointed even by my own low expectations.

--
My Galleries are at
http://picasaweb.google.com/trevorfcarpenter