The Bruery Autumn Maple Clone - Extract Version?

Tis the season and I'd like to try a clone. Only problem is that there is only one recipe out there and its all-grain. Would anyone care to help me convert it to extract? I'll probably shoot for a lower OG, use 4 lbs of yams (on hand), and use a commercial Belgian Abbey yeast (Wyeast Labs #1762?).

Recipe Specifics
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Batch Size (Gal): 6.0
Total Grain (Lbs): 13.5
Anticipated OG: 1.080
Anticipated SRM: 14
Anticipated IBUs: 23
Wort Boil Time: 90
Anticipated ABV: 10.0%

Grain/Fermentables
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46.5% - 9.0 lbs Domestic 2-Row
20.7% - 4 lbs Munich Malt
26.1% - 5 lbs Cooked Yams
3.2% - 10 oz. Grade B Maple Syrup (added at secondary)
2.8% - ½ lb CaraMunich
0.6% - 2 oz. Dark Molasses

Hops/Spices
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65 grams Libery (pellets, 3.0% AA) @ 60 minutes
1 ½ grams Allspice, freshly ground @ 2 minutes
¾ gram Cinnamon stick, broken into small pieces @ 2 minutes
¾ gram Nutmeg, freshly grated @ 2 minutes
1 Tahitian Vanilla Bean, split and seeded @ 2 minutes

Thanks!

I came up with the following...correct?

6 lb. Munich LE
3 lb. Pale LE
2/3 lb. Pale DE
1/2 lb. Caramunich