Fruit wines use around 3lb per gallon so you have enough for 2 gallons of wine, basically. That's what I'd do as I don't really go for flavoured ciders or cider-strength stuff based on other fruit - and because I don't do them I'm not sure how much fruit you'd need to get the flavour to come through at cider strength, or how much sugar you'd need. But I do love a good mixed berry|currant wine.
If you do wine, just mix them all up, it'll be good, and berries and currants are so low in sugar you can pretty much ignore it and add 1kg per gallon of ordinary sugar to give about 11%. But I'd also add about 200g or raisins or sultanas for tannin and winelike quality and with the berries that'd push it up to about 12.5%.
One way to do it would be to crush them gently (don't break the seeds) and mix with the sugar and enough water to keep it liquid, and ferment on the pulp for 4 or 5 days then strain to demijohns, make up to the gallon with water run through the pulp to get all the flavours and sugars out.
As they've all been frozen you can skip the usual Campden tablet, I think.
