Hello,
It's unfortunately not possible to use external effects from like Arturias FX Collection 4 in Analog Lab.
It's unfortunately also not possible in the individual full applications.
I'm not sure what you ask. And what you mean with "Just" a VST host.
(BTW effects also come as VST's. They are just VSTe's (e for effect) and not VSTi's (i for instrument).)
Analog Lab can play sounds from all Arturias software instruments without you own the full instrument applications.
But at the same time it also is a way to sell the full applications.
It's integrated with Arturia controllers.
If you own individual full applications, then you have the same edit possibilities in Analog Lab for that instrument, otherwise the edit possibilities is limited.
It's possible to combine two instruments in Analog Lab Multi instrument presets that only can be used in Analog Lab. The sounds can be layered or split.
Analog Lab have it's own build in effect section and a mixer. Those are are part of Analog Labs own preset format.
Analog Lab share and can exchange single presets with the individual full applications.
Analog Lab is in more ways a part of a system. It's a tool. It's not directly a instrument in it self as it use sounds from the full instruments. It also is'nt just a VST host for Arturias software instruments, and as said, then outboard effects unfortunately can't be used in Analog Lab as it is.