sorry to say i'm surprised they even let your g/f appeal (seeing shes not a family member, so she only has limited rights to an appeal)
1) yes you could, but they might ask why you didnt get married within the 6 months and if your applying for another fiancee visa, they might wonder if your just using it as a visit visa.. but if you married in the phils later instead, i wouldnt expect you to have any problems doing that.
2) on a fiancee visa, she cannot work til she has been granted FLR.spouse visa ? you mean if she came on a fiancee visa and you married and applied for FLR ? no she would not have to go back to the phils, as long as you married and appiled for FLR within the 6 months of the visa being granted, she would be here legally until she knows the outcome of her FLR visa app even if her fiancee visa had now expired.
3) if your applying for a fiancee visa and you can get a letter from the judge/lawyer stating that you will be granted a decree absolute within the next 6 months you could try and apply for a fiancee visa now, bit of luck you could be granted it..