For herbs, rosemary, oregano, thyme, lemongrass, etc, are easy to care for, basically weedlike. A bigger annual like basil can be fun and useful to grow, if a bit more finnicky and demanding when it comes to water, and might need it's own pot to produce enough to be useful. When in doubt, make sure it'll thrive in your planting zone and light conditions and keep in mind the symptoms it'll show for when it needs more water, sunlight, or when it might be bolting.
A few notes on potting and keeping plants off the top of the dome:
-You can probably find a planter that will fit on your railing or hang off of it, ideal for small spaces or if you want even more planter space. East-facing isn't as ideal as south-facing in our hemisphere, but it sounds like it'll be okay.
-If you're growing perennials or any plants that can't overwinter, you'll need to bring them in for the winter. There are a few ways to deal with bugs in the soil and not bringing them indoors with you, like flushing the soil out with mildly soapy water.
-For drainage at the bottom of the pot, you can go the more traditional method of rocks/ceramic shard/etc, use a cork or other porous material pad, or just use a few layers of coffee filters, it's really up to taste with likely only minor differences either way.
-Depending on what you're going for, you should probably look for a "soil mix" specifically (something that doesn't have any dirt in it) for a variety of reasons. These mixes are primarily hardier organic matter, compost, and drainage materials (like perlite), and usually avoid the issues that come from having dirt, like dirtborne pathogens and fungi.
-Eventually you'll have to fertilize, and the easiest way to do that is with a liquid fertilizer, especially organic ones you have to dilute. You may also may need to repot, if something outgrows what it's in and you want it to keep going, or if it's soil needs a refresh.
This was mostly me just spewing as much as I could off the top of my head, so if you have any more you want clarification on, feel free to hmu!
