You need to consider about the whole thing. buckets, resources, equipments and sanity, yes sanity. If i take a look on levels, it's okay for normal. However on hard, you are required to achieve certain goal to make your life a lot easier during the event. Example, like enough with fighters so you can grab AS. Type 3 shells if you have to deal with installation bosses, AP ammo against heavily armored boss or just for the sake against normal enemy BBs. Night equipments for easier time on night battle, some of them can be really hellish,ASW equipments is extremely important. Finally sanity, you be surprised what people can do when they lose faith, sunken ships, stupid moves, despair, stop playing the game and even on extreme case, sink the whole fleet. Well, you do have experience from the previous event so i suppose you know some of these stuff already.
Okay, let's take a look on the whole as fleet.
DD: Not exactly good for hard but you could use some of them. However lack of big pool of DDs. You always want to have several DDs on standby for several situation, example would be shiplocking. Not having Ayanami feels a bit a loss for you, she is a strong DD that comes with flares. People would often overlook which make me sad, i think you should at least grab her, get some of your current DDs to higher level and get some reserve DDs at least on kai.
1.You must get more high level DDs
2.Ayanami
3.Bigger pool of DDs
CL: a bit below, i suppose lack of Yuubari and Ooyodo can leave you a bit lacking. As i mention with DDs it's the same thing with CL, lack of few reserve can cause you problems in future but i expect this should be good enough. Kuma and Nagara is a good choice for your fleet if you want some strong additonal CLs. Isuzu is also a good CL to grab, equipment wise as stats.
1.You must get more high level CLs
2.Bigger pool of CLs
CLT: Good job with CLT, really good shape! HOWEVER, Lack of Ooi it's not good, you really need her for events.
1.Ooi
CA/V: Pretty good, get a bit higher level on those would be good.
BB: Good good, you even got a heavy hitter Musashi. Focus on Musashi and Mutsu for a bit.
CV/L: There is some stuff you need to work on but i think this will have to do. Mainly lack of CVs, might seems absurd to say like that but you really want CVs with high FP for your support. CVL can work for you as support or just add more BBs and CA but they are considerable more expensive and not always having a good FP.
I hope the information is not overhelming and i also hope i did not miss any important information... Oh well.
And now to the point with events. How hard can an events be on hard? The spring event 2015 was consider as joke for older players, plenty of players was able to complete it on hard without having to top tier fleet. However, winter event 2015 was actually hard and annoying, mainly the last map, E5. So things can vary a lot. 2014 Fall was rather easy, 2014 summer event was insanly hard, Winter 2013 was a small and easy event while 2013 fall event AKA IBS was,no, it's still consider the hardest event ever.
My answer, i can not, we can not predict how hard an event will be. My recomendtion is to prepare for the worst.
Let me show an example for winter event E5 how painful it could be, even with the best fleet However, do not feel that hard will impossible because it's not! If you can not do summer event on full hard, you always have next, if you are lucky, maybe summer event will easy on hard. Remember, clearing event is actually cheaper than farming, farming can cost you douable, tripple the cost of clearing, depends on your luck.
http://imgur.com/a/puJqg
Anyway, feel free to contact me anytime.
ArcticaFrost
Peace out!
PS, i miss spell a lot, sorry for my dislexia.