Q. Will I be able to plant regular impatiens in the spring of 2018 in Lower NYS Westchester Cty. without being affected by the blight that has
The impatiens blight is still a problem in most areas. You could try planting individual plants (rather than masses) in the garden or in pots, assuming that you can find a nursery that stocks them. Do not plant them in beds which had impatiens in previously. Of course, if the nursery plants are already infected this will not help
This link to the NYBG library site provides information on alternative plants - http://libanswers.nybg.org/a.php?qid=1141452.
It is not clear whether this problem will disappear in time. The severity will probably vary from year to year depending on the weather and other factors. Botanists are trying to develop disease-resistant varieties.