Important:
This answer is based on tax law year ending 28 February 2017.
Answer:
It is outside the scope of the service offered by us to comment on whether it is advisable for you “to take over as a financial officer of a company”.
There is nothing, from a tax Act or the Tax Administration Act, that prevents you from doing “in house Payroll taxes for them”. It certainly is possible to use your e@syFile (as tax practitioner), or the employer’s one, for the submission of the monthly and bi-annual returns.