There is a complication in using multiple relative clauses that is semantic rather than syntactic in nature. Your first example involves serial, coordinated relative clauses. I've chosen examples I prefer to work with:
*/? I know some people who work with toddlers and who like grapefruit.
I'd say this pairing of clauses would in most contexts be too semantically disparate to work.
I know some people who work with toddlers and who attend karate
classes.
This works better, the contrast being acceptable. These are {people who both work with toddlers and attend karate classes}
I know some people who work in computing and who could [therefore]
probably help you.
Here, the second clause follows on naturally from the first. If the optional therefore is included, the first clause is of course non-optional.
In the following examples, the serial clauses would not work:
*There are a few people who/m I've met and who know all about the
dextroboper problem. [and who like grapefruit ...]
It doesn't make sense to serialise such disparate statements
There are a few people, who/m I've met, who know all about the
dextroboper problem.
ie there are only {a few who know all about the problem}, and I've met them all: 'who I've met' is a parenthetical
There are a few people who/m I've met who know all about the
dextroboper problem.
ie amongst {the people I've met}, a few know all about the problem.
Looking at your second sentence,
I can name a few people who I'm friends with and who got a job in that
company.
is again a coordination.
I can name a few people [who I'm friends with] [and] [who got a job in that
company].
But in your
I can name a few people who I'm friends with who got a job in that
company.
there is not coordination, but sub-setting (nesting of clauses):
I can name [a few people who I'm friends with {who got a job in that
company}].
cf
I can name [some friends {who got a job in that
company}].
The 'who' can't be dropped in 'standard British English' in the first of these two sentences, and dropping it in the second sounds like an informal AmE usage.