Filipina requirements on moving to Dubai

Not clear on what your question is but I think you are confusing totally different things.

To split it apart:

1) You CAN convert from visit visa to work permit IF there is an employer willing to sponsor you.  Or in other words, yes, if you get a job
2) You can get married in the UAE if one of you has a residence visa and the other party undergoes pre-marital medical checkup
3) If you get married to her, YOU can sponsor her for a family residence permit which allows her to live in the UAE but NOT to work.  If she wants to work then guess what?  yes she HAS to find an employer / job

So the difficulty you heard about obtaining a work permit is simply difficulty in finding a job.  Or in other words, you can be resident in the UAE through marriage / family ties but can't work or be resident here with permission to work - which can only be through an employer / job. 

As far as the other friend is concerned, she has to follow the same process but unlike your wife to be, her timeline is till the expiry of the visit visa.

Hope it's clear now.