In a paragraph of introduction to this poem W.F.Bolton (1965) suggests that the preceding sentence is meant to 'draw the poet - and his audience - into the abstract scheme', implying that the 'spræc' is the first seven lines of the poem, and that what has been said in them 'is no small assertion to make'. This is a feasible and attractive translation, but 'spræc' in line 101 is definitely the conclave to which all souls are summoned.
Bosworth-Toller (1921) suggest 'after terror has become the portion of the spirit', but I assume that 'gryre' here means 'what causes terror', not 'the state of being terrified'.
'Godes dæl' could mean three things: (1) with short vowel in the first word, 'the share allotted by God'; (2) with long vowel, 'the share allotted to the good man'; (3) with abstract sense, the share of good fortune, the quantity of good things standing ready for the righteous in heaven. I have chosen the latter translation largely because of the analogy with 'þæs brogan dæl' in line 71.
There is no gap in the MS, but 'fisces eþel' is not an acceptable variation of 'wætres', even if there were no break in the alliteration. In 1857 grein suggested 'and frecne grimmeð', 'and the home of the fish rages furiously'. This is a good line close in phrasing and context to Riddles 2,5, 'hwælmere hlimmeð, hlude grimmeð'. My own more unimaginative proposal assumes repetition from lines 1-2, in the same way as line 37 echoes line 9.
'Lyftes mægen' might mean ' the power of the sky' in some more general sense than I have translated it.
'Oncweþan' means 'to reply'; B-T (1921) suggest tentatively that the phrase here means 'make (this) response'. I think that the poet wants his readers to say what follows to themselves; 'ic' in the next line refers to us as well as to him. He is telling us the moral of his poem in the most direct way possible, concerned as always lest we should read it but not believe it, not act on it. Mackie (1934) translates similarly.