I can comment on your second question. Impact factor is generally not recommended as a criterion for researchers' performance assessment. E.g. the REF procedure, as many other evaluation practices, does not assess impact factor. Many reasons could be mentioned like incomparability with scientific quality of particular publications, high differentiation by S&T fields and topic coverage, and so on. There are plenty of studies that have shown drawbacks and limitations of IF as a performance indicator - just address to any source (e.g. Google Scholar).