Obviously #21 and #30 would get replaced because those trucks where leased (but again CFD may have purchased one or both of them, and now CFD maybe using them as spares as others people have pointed out on other threads)
And also #21's and #30's districts need to have some sort of Aerial coverage. I believe these two trucks will become Aerials again when the new fire station in Seton, and #34's new Tri-Services station open's and one of the current rigs in both #21 Station and #30 Station respectfully gets shuffled to one of the new Stations.
There are 8 of these new Quints, and basically ever Aerial needs replacing. Heres what i think will happen....
CFD will replace Aerials: #1, #6, #8, #18 (And #18's becomes a spare Aerial.. they did this with Rescue R1306 because all of there Rescues were to old), #19, #21 (Already in service), #30 (Already in Service).... and the final Aerial could go into Station #32, or it could go into the new #5 when it opens because there was an Aerial ear marked for that station.
If CFD did what i think they did; they could/would put #30's leased 105' Smeal Sirus Aerial that they may have purchased into Station #32 because #32's first run area primarily consists of residential/mixed occupancy multiple dwellings and very little if any industry.