there are any limits to what kind and how many creatures can you create with this spells?
There are no hard rules although both are spells that require careful adjudication by a Judge.
For instance, conjuring an illusion of 1 big dragon is likely much easier than conjuring an illusion of 200 dwarves, in turn much easier than conjuring an illusion of 200,000 scarab beetles. At some point the spell's ability to realistically represent that much movement and detail would (must) break down.
Where and how to draw the lines seems heavily contextual... how close are observers? what is the terrain? etc.
thank you Alex!