I know exactly what the Fox River Fifty is because I have one and I've seen others. They're worth about $75 to $100 in good shape. If it was nickel or minty it might be worth a little more up to $125 but like mykeal said, condition is important as is the selling venue. I know where there is one for sale on line for $79. If there's any rust in the bore, then it may not even be worth $79.
Next you say that you have a Jukar rifle that's a .45 caliber percussion. The only Jukar that I can think of is a Jukar Kentucky rifle with about a 33 inch barrel and I once had a brand new one. That is not a very expensive rifle. The value could range from:
$50 - $75 in poor or questionable condition
$90 - $125 in fair condition
$125 - $150 in good condition
$150 - $175 in very good to excellent condition
$175 - $200 in new or mint condition
Most Jukar Kentucky rifles sell for about $90 - $110 in average condition, and not many sell for more than $125.
So you may be looking at selling your 2 guns for about $200 more or less if both of them are at least in fairly good shooting condition without any rust issues inside the bore or on the outside of the gun, in and around the nipple area and such.
If the bores are in poor condition, then sometimes just the stock and lock are worth 1/2 the value of the average price of the whole gun.
Now what about the matching pistol that you're talking about?
It's also a Jukar and how long is the barrel?