If they're truly dwarf trees, you should put in permanent stakes. Do you happen to know what the rootstock is?

I do not know what the rootstock is....r trees commonly labeled dwarf and end up not being so?

I agree with ltilton, staking is a good idea, and if you can find out what the rootstock is, it will help in knowing how to manage the trees. If they are on semi-dwarf rootstocks, then they will need to be planted at least 12-14 feet apart. If they are on dwarf rootstocks then at 8 feet high they are already almost full grown and can be planted at least 9-10 feet apart.

Red Delicious is also a parent to Fuji so they might not pollinate each other very well (incest), and Jonathan will have to be the main pollinator. So, in my opinion all four trees should be planted so that the Jonathan is within about 50 feet of all the other trees as the prime source of pollen for the other three trees.

Be aware that Fuji is more of a warm climate variety and might not perform very well for you in Zone 5. That's not to say it won't work, but don't be too surprised if the apples never fully ripen before winter sets in.

Another special thing about Fuji is that it is a tip-bearing tree. Most apples produce fruit on short spurs throughout all the branches. However, tip-bearers require special care in that they produce a large proportion of their fruit on the tips of last year's growth. So, you'll want to prune your Fuji trees less harshly than normal, because if you cut off the tip of every branch you could lose up to 90% of next year's fruit! Nevertheless...

Next March, you should prune all the trees to remove roughly 1/3 of all the wood, including cutting about 2 feet off the top of each tree. This will help your trees to adjust to their new surroundings. There are a few good sources on the internet (as well as in books) as to how to prune trees. Some of the best sources I have found include:

http://eap.mcgill.ca/CPTFP_7.htm
http://www.pubs.ext.vt.edu/422/422-021/422-021.html

Best of luck to you.

If they are already 8 feet tall, I'm guessing that they are potted, not bare root (it would be early for BR anyway, I think). Given that many of the suggestions to removing wood are to balance the top with the bottom (which has just lost root system due to BR transplanting), I would think that wouldn't be needed. Further, it could delay fruiting. From what I've read, you get earlier fruiting by not heading back branches. I would instead just plant and stake the trees. I would normally say bend the branches more horizontal, but I'm not sure it would matter at this time of year- any fruit buds which were going to form this year are already there...