If you plan on shooting a lot, I would also suggest the .22lr over the .17HMR, but either will be a ton of fun. Aside from cost, one of the beauties of .22lr is the almost limitless range of ammo choices available to you. You can experiment and try dozens or hundreds of different loads if you like, and it's a sure thing that some will shoot much better in your individual rifle than others. The .17HMR has only a relatively small number of factory loads available. For many years all the .17HMR ammo on the market was made by one manufacturer and was, except for varying bullet weights, pretty much identical; not sure if that's still the case, but for sure the variety doesn't compare to .22lr.
For shooting a lot, I would suggest spending the money for a decent quality scope of around 3-9x or 4-12x, rather than buying some junky higher power variable scope. A quality scope will allow you to see your target clearly; a crisp clear image at 9x is far preferable to a dim, foggy 20x view that appears as though you are looking through waxed paper. You will always regret buying junk, especially when it comes to optics. You will never regret quality.
Parallax adjustability is okay, but far from essential. If you shoot at 100-200 yards, you are right in the range for which most fixed-parallax centerfire scopes are factory pre-set. For target shooting, fiddling with an adjustable parallax can be interesting, but I'm not sure that a beginner wants the added complication. For hunting, parallax adjustability is largely a crock; once you get to super-long-range "hunting" and know what you are doing, maybe. For most typical hunting, an adjustable parallax is not only unnecessary, but largely a hindrance. Developing good form, which includes keeping your eye centered behind the scope, eliminates parallax.
Let's face it, no matter what you buy there is a good chance that some experience will tend to have you leaning towards certain features and away from others. Buying a quality rifle like the Tikka, mounting it with a quality scope and learning to shoot properly will strongly increase the odds that you will still own, use and enjoy that first rig for many years to come.