will niche sites on page 2 of google make conversions

In short, no.

If you take a keyword that gets searched 10,000 times, if you are on page 2, at best you are looking at maybe 10 visits a month.

Yes you can get conversions...the percentage will be far lower as not as many people will search that far past the first 5 results in search.

If you optimise the heck out of your content and make it relevant t an engaging you will maximise your chances

Of course you can get conversions on page 2. If nobody ever visited page two, it wouldn't exist. In fact, the top spot on page 2 usually gets clicked on slightly more than the bottom position of page one. Obviously, being higher up on page one is ideal, though. I frequently click on results on page two, three or four when I haven't found exactly what I am looking for in higher search results.

I'm not sure why you are asking the question, though. Nobody should have a goal of getting to page #2. We would never optimize around a phrase if that was our most optimistic projection. Page two is just a step on the way to page one.

And, of course, it depends on the number of searches how often you will get clicked and many other factors on how often those will lead to conversions. If there are very few searches for a term, it could be years before you see a conversion from page 2. If there are tons, you could get several per day/week/month, depending on the number of searches.

In my experience, if you aren't in the top 5 entries for a certain keyword phrase, you might as well not be there. Sure, you might get a little traffic but it won't be enough to be worthwhile.

Page 2 is a big no-no.