Don't rely on one program to tell you your keyword(s), it will help you find some POTENTIAL long tails, but dig in manually after that.
Google the long-tails, run the top 5 sites through AHREFS, MOZ, Majestic. How are their backlinks? How strong are the sites? What other related keywords are they ranking for? Put the sites into Google Keyword Planner, now you know what keywords Google thinks are good for them, review those keywords.
Lather, rinse, repeat.
How much time over the next month? 10hrs a day, a week, the month? What kind of investment of time we talking?
How are you at writing content, if you can pump out, good, QUALITY content on the niche, then schedule some posts to drip in over the next 3 months(or more), it will look like the site is still active. I have sites where posts are scheduled out 6 months in advance(helps to be a totally evergreen niche), so don't fret on that.
The amount of time it takes to rank is just too broad a question, I have had sites rank in top 10 in 1 month, and another yr old site is just breaking top 20(VERY difficult niche). It depends on your site internals and then your external work. You can have millions of links, but if the site is full of horrible content, poor internal linking, and so on, you may never rank. If you get into an easy niche, with great on-site work, and some quality backlinks, you can move up the servos easily. It has so many factors, no easy answer there.
My personal playbook for page amounts for a micro-niche site are as follows:
Homepage- good 1,500-2,000 word article, all about the niche and your main focus keyword, with several long tails and LSIs mixed in.
About me page- good bit of 300-500 words about why you(you personally, your web persona, or the company the site represents) is the authority of the site, toss in your keyword here too.
Contact me page- nothing fancy here usually, just a simple email form.
As for content, it will matter the style you are going with, full silo, partial silo, scattered blog, first decide on your style, then it helps dictate the amount of posts to start with after that.
My PERSONAL rule of thumb is to have smaller (400-800 word) articles focusing on a single long-tail, then link them in a silo or wheel style to a power article(1,000-2,000 words) which is targetting a single keyword, with 1-2 long-tails really pushed, plus 2-3 LSIs. You can even drive this further to making small articles about an LSI, then circle/silo 5-10 posts to a long-tail focused post, then circle/silo 5-10 of those to a power article(single keyword). Doing the first style, I usually end up with about 12-15 posts driving to a single keyword.
Good shared hosting should be fine to start with, just make sure they don't keep your site speed throttled back.
Anything else?
