Is an XV 8 commander with 4 cyclic ion blasters good?
It is, but arguably not as good as a Coldstar with 4 Fusion Blaster. That's a first world problem thing for min-maxing tho. CIBs are really strong and even more so on a BS2+ platform.
Cyclic ion Raker or big fusion gun on the Ghostkheel?
Definitely the Cyclic Ion Raker. The Fusion Collider is basically just two Fusion Blaster. The CIR is good against vehicles as well as infantry just like the CIB but also has 6" more range than the FC so it helps with staying away and benefitting from the stealth effect. I recommend taking Fusion Blasters as secondary weapons.
While it's tempting to go all dakka with double Burst Cannon and improve both weapons with an Advanced Targeting System it doesn't do as much damage as one would like and both, the CIR and Fusion Blaster are pretty self-sufficient so you are free to take for example a Shield Generator instead of the Advanced Targeting System. The Target Lock is mandatory tho or you're too reliant on getting 4 Markerlight hits on your target and the Ghostkeel often acts where Markerlights don't get easily Line of Sight.
I'll field some crisis suits probably with two weapon systems. I bought some used that have a rifle and misile pods. Is tri weapons worth it? I probably won't do 3 CIB cause I only haven 3-4.
Unless there is some huge change in CA (which I doubt) always go with three weapon systems. None of the support systems is as efficient as simply taking another weapon unfortunately.
Mixing weapons is also not recommended. Especially not something that wants to stay away like Missile Pods and something that wants to be within 12" like the Plasma rifles. Building allrounders is always a bad idea. Instead of being good at their job you end up with a unit that is bad or just mediocre at two jobs ... and Crisis already have problems being good at one thing anyway.
If we want to talk specific weapon loadouts it'll be quite a bit longer post tho so just let me say this:
Plasma Rifles and Missile Pods are the two worst weapon choices for Crisis currently and the only worse choice is the Airburst Fragmentation Projector. Cyclic Ion Blaster can do everything the Plasma rifles and Missile Pods can do better plus more.
Fusion Blaster would be an okay-ish choice if there wasn't already something like Coldstars, HRR Broadsides, RailHeads, Riptides and even Ghostkeels.
Burst Cannons are a cheap alternative to the CIB against less armoured infantry.
Flamers are great as well if you go all out on them. Just let the Crisis start on the table surrounded by drones and advance every turn (8+1d6 inches with FLY is a lot of ground they can cover).
Again all these things of course can change with CA.
If my posts appear rude to you, I apologize. It's not meant to be rude in any way, it's just the way folks are in my country. It's really more about being direct than being rude. I know how it's perceived in the english speaking community and I already try to tone it down but I barely notice when it's too much since it's normal for me.
So yeah, I'm really not rude it's basically just cultural differences that act against me here. Again, I apologize.