Are Solid State Relays Noisy - EMC?
The SSR will almost certainly produce less EMI. A physical relay can suffer from bounce and repeated transients due to the rapid current and voltage fluctuations this can induce. Breaking the circuit while current is flowing can also create noisy sparking. SSRs do not have these problems.
Resistors are not strong sources of EMI, don't worry about that.
The key to reducing EMI from any switch is to perform the switching as slowly as is practicable. This reduces both the peak of the switching transient and also the presence of the higher frequencies which cause most of the trouble. Best to avoid operating the SSR - or any switch - with a fast rise time. If you have to and it causes problems, then slugging the input with a low-pass RC filter is something you might like to investigate. But don't switch too slowly or you might dissipate too much power in the SSR and damage something: data sheets are your friend here.