HST:
only about 30%-50% of the people that use rogaine find it helpful. an even smaller group is super responder. i have no idea if minoxidil is working for you. who know if you are not using it in the first place, you will even lost those hair you are having now. alot of people only realise their treatment is working once they stop using it. you can also switch to rogaine foam for higher chance. it work better than the liquid version.
hair that is not help by minoxidil will not be affected once you stop using it. only those hair that grow due to minoxidil will be lost once you stop using it.
if you stop your treatment, you will get a shock loss. but it will grow back until the state before you have use any treatment. it should not make you lost more then you have at the first place.
as for your proscar question, just do some maths and you should be able to know how long it can last. but i wonder how are you going to cut a small pills into 10parts. 0.5mg does work for some people. you can try and move on the stronger dose if you have to.
lasercomb should help in some way. but it should not be your solo treatment.
there are other possible treatment as well. just a advice, go read up more rather than bombing ton of questions to others. frankly i hesitated in answering you due to the way you are asking question. it like you are asking others to spoon feed you with answers. further more, some of your questions require long answers or just common sense. hope you understand.
good luck.