I have 4, who are 5,4, 14 months and 1 month, so similar age for the youngest 2!
I think that it is impossible for one of them not to be crying at some point at this time of the day, and I also find it quite manic! DH is not home until 6:30 at the earliest, and sometimes not until later than that, so have to manage bedtime for all 4 on my own!
My 14 month old nearly always has a bath, as he is always filthy by the end of the day! 1 month, only bath if necessary, and try and work that in with a weekend when DH is around. 5 & 4 year olds, try and bath every other night, unless they are actually dirty!
Usually try to get tea out of the way earlyish, and do baths at 5:30. DC4 usually in her basket downstairs, sometimes asleep, sometimes awake and crying, but try to ignore to sort out the others into their PJ's. Then 6pm, DC4 has a bottle, also try and keep DC3 amused while this is going on - singing, stories, getting the older kids to play with him a bit. 6:45ish DC3 goes to bed, DC4 back in basket, again ignoring the crying if she isn't asleep! 7pm DC1 & 2 go up to bed for stories. Read to them both together. Then DC4 has cuddling time in the evening once all the others are in bed.
Have to admit, it is quite hectic at the moment. The worst thing I find is if tea is late, as it throws everything else out! Just keep telling myself this is the hardest time at the moment. Must admit it makes such a difference on the weekend when DH is around for the whole tea/ bathtime routine!