1 gallon of honey is about 12 pounds of honey so good for about 4 gallons which is close to what you will have in that recipe.
For yeast, you're going to get differing opinions, the package info on 1118 is that 1 gram is good for UP TO 6 gallons. there has been much debate about pitch rate, many like to go with the up to value, I prefer to use 1 gram for 1 gallon, 2 grams for 2-3 gallons, and 3 grams for 4-5 gallons. I always recommend rehydrating over dry pitching, in my experience anyway it cuts down on the lag time in the begining.
For the amount of honey you are using and other ingredients, using 1118 is going to produce a very dry end product, which is great if thats what you are looking for.
For nutrients, if you are going to use only the orange juice and raisens you're going to want a fair amount of raisens probably 75-100 or what I'd guess is at least a full one of those small snack boxes of them if not two. If you have a surplus of yeast or can stop at the grocery and get some bread yeast, you can take about a gram of it and add it to a cup of boiling water and simmer about 10 minutes and after it cools down add that in as well, you're definitely going to want that much extra stuff to feed the yeast.
Personally I'd save the cherries for the secondary or at very least the very end of primary fermentation, it will help you retain much more of the cherry flavor and aroma, and you may want to increase your quantity if you can to at least 1 pound per gallon if not 2. (if you have some vanilla beans around they go great with cherries and help balance the overall flavor as well)
make sure you aerate (shake the sh!t) out of your must when you first make it and daily for at least the first few days (just start gently so you don't make a geyser)
if you don't already have one, invest the $6-$8 dollars on a hydrometer, they are invaluable.
besides the forums here the link below for the gotmead.com newbee guide has tons of great info for people when they are first starting out, and never be afraid to ask questions here.
Good luck and welcome to the incredible, obsessively addicting world of mead making