Hi and welcome to the boards! I'll try and answer your questions but have no experience with twins so may ask for a bit of twin help!
Sounds like you are doing really well with them!
They are technically too young for a 4 hour EASY but formula babies do often go to a 4 hour feeding routine before breastfed babies. If they are content on 4 hour feeds you can leave it, but you will have to do a different EASY until their A time catches up in a couple of months. Mine went to 4 hour feeds around 12 weeks so we did EASAESAE or some variation until they caught up. It works, you just need to watch that you don't feed to sleep when E comes right before S.
The dreamfeed can take a while to get used to but some babies don't dreamfeed well (I have two like that!) so you can either try for week and see if it gets better or leave it and maybe try again when they are a bit older.
Cluster feeding you are already doing! Splitting the feed around bathtime is clustering as they are taking more with the two feeds close together than they would at just one bedtime feed. Are they draining their bottles? If they are you need to add another oz into the bottle so they can stop because they are full and not just because the bottle is empty.
If you have a look at this link
http://babywhispererforums.com/index.php?topic=164253.0 you will find some examples of EASY routines, maybe look at the 4-6 month link to fine some 3.5 hour EASYs
Does that help?
Laura