Are there different penalties for crimes against a PCSO as opposed to a police officer?
No a PCSO is an Emergency Worker so the starting point and aggravating features for sentencing are the same.
Regarding murder sentencing/whole life terms, which have special police enhancements: does police include PCSOs?
I have not been able to find any citable sources that can directly answer the question, but Section 3(1)(b) of the Assaults on Emergency Workers (Offences) Act 2018 defines a PCSO as an Emergency Worker:
a person (other than a constable) who has the powers of a constable or is otherwise employed for police purposes or is engaged to provide services for police purposes
Section 4(1)(2) of Schedule 21 of the Criminal Justice Act 2003 lists examples when a whole life order may be appropriate, including at s.4(1)(2)(ba):
the murder of a police officer ... in the course of his or her duty
This list is neither exhaustive nor definitive so it is likely that, based on the Emergency Worker definition and as long as all the relevant criteria are met, the murder of a PCSO may well be covered by this provision.
I note that the investigation in to the murder of Julia James is ongoing and potentially sub judice so my only observation is that according to media reports she was not on duty at the time of her death so s.4(1)(2)(ba) may not be applicable.