keeping both numerically and factor coded factors

Dear list,
looking at the correlation values of my random effects, as well as the
fact that my model fails to converge, it makes sense to me to simplify its
random structure (while keeping maximal and according to our hp the fixed
structure).
One way is to remove correlations, and I know that the || notation works
only with numerically coded factors.
As far as I understood, I have two options:
1) use the package afex, putting my model as object of mixed and adding
"expand_re=true"
2) use the original factor, by default read as "int"

I want to use the option 2) because with mixed I can't apply the PCA
function for random effects to check if my model is over parameterized.

My questions are:
a)    is it true that I can use my factor as it is when read by R, i.e.
"int"?
b)    if yes, does it make sense to keep in the model both the factor in
the nominal form as fixed effect and the factor in the numerical form as
random effect?

Many thanks for your help,

Elisa Monaco | PhD student

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