The brick will add a nice pop of color next to the grey. You can also add some of that similar color (brick and grout) with pillows or throws on the furniture.

"Apparently, my neighbor has done the same thing without issue. Someone on my block had told me this." And your neighbor's house is identically constructed and you are sure nothing has been weakened or settled? I'd want more assurance than that somebody -- probably with no knowledge of construction or engineering -- told me it would not be a problem.

Congrats on your new home! Your cabinets are not shaker style, these are raised panels cabinets :) I think painting the walls lighter color is a very good direction for a smaller, darker space - you should probably continue going in that same direction for the kitchen as well. I'd at least go with painting the cabinets (white / off white). If you can spend more, I'd also replace the countertop + backsplash (countertop - maybe a light quartz with very delicate veining in it, backsplash - white/gray subway/square tiles or something more sophisticated, if you'd like, but keeping it on the lighter side - and doing a full backsplash (i.e. from the countertop to the bottom of the upper cabinets), as opposed to the 4-6" counter-splash that you have right now). You can theoretically replace only the backsplash without replacing the countertop - but it will be trickier to replace the countertop down the road (the "rule" is that backsplash is installed after a countertop is installed) - so keep that in mind. Appliances look decent, assuming they are in good shape - keep them until they stop working :) I think your cabinet knobs are wood - you can change them to metal - black or oiled rubbed bronze will look fantastic with light cabinets, maybe go with square knobs for a bit more modern look, if you're a fan. Good luck!

I would definitely be tempted to add art. Take your time finding something that speaks to you instead of something off the shelf. If you choose well you can enjoy it for years to come. Also nothing wrong with having the toddler play area there. If it keeps the child within your sight and entertained then that's a good use of space. :-)