Could you convert your example to phonetic english? Spelling is one thing, pronunciation another.
In rough English approximation: güf thæm men ÆL-dun THEES-nuh für, where ü is as in German and æ is the vowel sound in 'cat' in most dialects (i.e. not in the dialects of Scotland or New Zealand.)
1. the <g> in the first word manifests in that particular phonological environment as [j] (palatal approximant, as in English "y"), if I'm not mistaken.
2. The <ie> is pronounced either [i:] or as a diphthong [ie] (but probably not [y]). The diphthong is probably older, and sort of has an Old Saxon twang to it, if I may say.
3. <ea> is not pronounced [æ] but rather as a super cool-sounding diphthong, [æɑ].
4. There's not consensus as far as I know about the pronunciation of <r> in OE. I tend to go with the alveolar trill, but other options are the alveolar approximant (as you have suggested) and the alveolar tap.
So, an amended pronunciation gloss might look like this:
yeef thæm ÆAHL-dun men THEES-nuh für.Thanks. I'm sure all agree that's much clearer.