There's a lot of options here. What type of fish are you wanting to keep? I'm currently running four sumps. Three of those are multi-tank setups. The tank configurations are varied and each has its own issues.
Depending on how you are distributing the water, ( each tank has its own supply and drain, or some sort of daisy chain, or a variant of both ) your pump requirements may be hard to pin down. You also need to consider head height, or the distance your pump will need to raise water. I would suggest using separate pumps for each level of tanks and a separate pump for your 55. This would mean that you would have more flexibility in using less expensive pumps. I currently have Mag, Quiet One, Rena, Rio pumps and they all do their job. If I were you , I'd check out specs for gallons/hour, head height, and wattage before purchasing.
As for air, I'd look at how many outlets I'd need, how I'm going to distribute the air, etc. So may options here I hesitate to say. I would recommend though that you buy some sponge filters and keep one or two running in the sump. Then if you suddenly need to isolate a tank, you'll have a mature sponge ready for it. They're cheap enough so it's less of a hassle than trying to make your own (IMO).
If you post more detail, we'll be better able to make suggestions.
--- Dave a.k.a. front-fan
There are 10 kinds of people - Those who understand binary
And those who don't