First of all, the numbers you get at six weeks are effectively your baseline numbers (yes, they’ll be a bit different from a real basline taken before you went keto, but not that different). Wait until you have been eating a ketogenic diet for six months before taking any action on the numbers you get. It takes that long for things to settle.
Secondly, why are you worried about your cholesterol? The only number that has any predictive value for your risk of cardiovascular disease is the ratio of triglycerides to HDL. If you want to lower your triglycerides and raise your HDL, you need to eat saturated fat. Polyunsaturated fat will lower your LDL cholesterol, but at the cost of doing other damage. The only polyunsaturated fatty acids that you need to eat are ω-3 and ω-6, and not too much of the latter, because it is inflammatory. So stay away from seed oils, which are all high in polyunsaturates, and cook with butter, lard, tallow, bacon grease, or fruit oils such as avocado, coconut, or olive.
Third, did your doctor order an NMR test to see what pattern of LDL you have? It may be too soon to all be pattern A, but it would be good to know where you stand. As far as all the research has shown, cholesterol level is not related to risk of cardiovascular disease. Many people with familial hypercholesterolemia (a genetic predisposition to elevated LDL) never develop heart disease, never have a heart attack or stroke, and die at perfectly normal ages from perfectly normal causes. And most people admitted to hospitals with a heart attack have low LDL.
All this tends to indicate that cholesterol does not cause cardiovascular disease. In fact, a number of large, significant studies have shown that higher LDL actually seems to correlate with a lower risk of heart disease, especially as we age. What seems to give cardiovascular disease to people with FH is mutations that make certain clotting factors (in particular fibrinogen and factor VIII) more active, increasing their risk of a blood clot. If you want a real measure of your risk of CVD, ask your doctor to order a CAC scan, since even sticky blood is less likely to be a problem if your arteries are undamaged.
Last, each period of fasting, whether it’s days or only 12 hours between one meal and the next, is a period of low insulin, so fasting should have a positive effect on your HbA1c. However, HbA1c is a measure of how glycated your hemoglobin is, and since red corpuscles generally live for three months, it is not going to change all that much in six weeks. It is a good indicator of your stroke and heart disease risk, because glycated red corpuscles are stickier and therefore more likely to form an obstructive clot.
