These are the FA flavors I had:
Custard, Vanilla Tahiti, Catalan Cream, Vienna Cream, and Orange, plus 0.5% each Mandarin, Marzipan, Marshmallow, and Torrone
Versus your ingredients:
4Tbls of custard sauce, 1/4tsp almond extract, 1/8tsp orange extract, 1tsp of whip cream, 1/8 tsp. of vanilla extract. When this concoction was tasted side by side with the liquid ice cream it was close enough for me. Could have maybe used a little more custard vanilla creaminess.
Translating your ingredients directly into flavorings, it's FA Custard, Almond, Orange, Fresh Cream, and Vanilla Classic. But I still think the other flavorings I used will make it more appealing. Getting enough sweetness will be really important. I'd skip Fresh Cream completely because it's not sweet - and let Custard, Catalan Cream, and Vienna Cream do that work. FA Custard IS that custard you made, but with lemon added. Some combo of Custard-Catalan-Vienna will work, but you might want more Custard and less of the other two. The biggest question mark for me is which almond flavorings will do best for you. FA Almond smells like almond extract but isn't prominent in recipes; when you use enough for strong flavor, it tastes more like actual nuts or almond meal. FA Marzipan is extra sweet, very like amaretto, and stands out in a recipe. I'm confident it has a place here, for the sweetness if not the impression of amaretto. Torrone has sharp citrus notes, also quite sweet - you might omit this (because of the sharp citrus) and use Almond instead. If you include Marzipan, you probably want the Mandarin in there to help prop up the orange flavor. I used Marshmallow for the extra sweetness and to smooth Marzipan, so I'd suggest keeping that. FA Vanilla Tahiti is a cherry-almondy vanilla, the sweetest they make - but FA Vanilla Classic is more like generic vanilla extract in a typical kitchen. so...I'd add Vanilla Classic and Almond to the list, and perhaps omit Vanilla Tahiti and Torrone, so you end up wanting: Almond, Catalan Cream, Custard, Mandarin, Marshmallow, Marzipan, Orange, Vanilla classic, Vienna Cream. If there's one you might not need in that list, it's Mandarin.
Let me mix this and see if it tastes good!