Regarding the G34, it's unlikely a beginner will get much better performance out of the longer barrel, however the longer sight radius can have a pretty surprising effect, a small increase can make a big difference for some eyeballs. What will absolutely have an effect is the trigger on the G34 - it's typically 1 or 2lbs lighter than the connector in the stock factory G17 (Some G34 come with a 4.5, depending when it was made, sometimes a 3.5lb trigger connector weight). The lighter trigger can make a difference for new shooters, particularly women. IMO the slide should be fine for the average woman shooter in terms of the strength required in the grip to cycle it. There are other pistols out there with various dual spring designs, HK comes to mind, which have very light and easy slides to manipulate, but Glock in my experience teaching women shooters are fine in this regard. You can mess around with aftermarket guide rod springs/etc, however there can be negatives to making the slide lighter in this manner, functionality problems/etc, but I have seen this work if it becomes a major issue. It's mostly a technique issue, not a power issue, as I've seen 13 year old girls on the range who were able to properly manipulate every striker fired handgun they tried.
Since you aren't worried about CCW/carry, and this is a home/range only pistol, the G34 is IMO absolutely an option to look at for you. Since it's very unlikely you're going to be in an environment where the cutout on the G34/etc series will get foreign debris in it, I wouldn't sweat that at all.
So far as a .22 kit, they work fine, and are a good way to train cheaply as well for new shooters, women, children, etc. IMO care should be taken with training with .22 if you're expecting your wife to use the 9mm for home defense - what I mean is be sure she doesn't develop a flinch due to anticipating the larger recoil impulse the 9mm has due to being "spoiled" by the non existent push and low noise the .22 has.
Millions have used the G17/34 (and 19 but you've ruled that out) to good effect for what you have in mind, range and in the home as a defensive tool. There are other options of course, other systems such as a double action/single action, and so on, so just find the one that fits your hand(s) best, your budget, and then train/practice with it. In addition to the .22, you may want to look at the various dry fire/laser options out there for the Glock, you can do a lot of great training on your fire control/trigger press indoors at home with one of the laser dry fire units out there.
