Here is my opinion about the questions you ask; note the word "opinion" since hard data is difficult to find.
1. Recurrence risk for PRE is generally considered to be considerable if the prior pregnancy was associated with severe AND early (late second trimester, very early third) disease. A patient presenting at 24 weeks with severe preeclampsia probably has a recurrence risk of approximately 40-50% at most. When PRE affects two pregnancies, the applicable risk factors include time of onset of disease, eventual disease severity, age and race of mother, singleton vs multiple gestation, whether or not she has a new partner, and so forth. It is complex, multifactorial and a best guess estimate in general.
2. Renal data from Australia as I recall is consistent with the persistence of renal effects of PRE as long as six months postpartum. Most of the effects of PRE on edema, blood vessels and blood pressure, etc. are transient and disappear with the eventual removal of all trophoblast tissue and pregnancy products. There is growing evidence to suggest that PRE during pregnancy may uncover a patient's inherent propensity to develop hypertension and cardiovascular disease later in life (notice we said not cause it, but uncover it since the risks are already there by genetics and other soft factors such as nutrition, etc), but it is not a lasting effect per se of preeclampsia.
3. As better information comes about regarding the utility of testing for certain factors which antedate the development of PRE during a pregnancy, better information likely is to be derived.
4. Consider each pregnancy to be a unique event, consisting of a genetic combination from both parents that are impacted by the mother's health and other soft factors such as nutritional status. She can do something about the latter, and she should. The former is out of her control (her genes and those of her partner). Counting upon the uniqueness of each pregnancy, a potential mother is encouraged to focus upon what she can do to maximize her health (exercise, diet, elimination of obesity, etc.) and then to undertake pregnancy with the medical assistance of a competent provider wherever she may live (an OBGYN that is board certified in OBGYN or subspecialty certified in MFM). If she has significant underlying disease of any type or is not a good candidate for pregnancy in general, it may be preferable to forego pregnancy altogether and not risk the complication of superimposed PRE upon an already fragile health situation.