If you really have the money to spare (babies are expensive!), then get the G34 and spend some time with your brother (so long as that doesn't take away from time with your child). I'd skip the G26, since you already have a G19. Since you seem to use your SBR AR very little, I'd not recommend getting another or dumping more into the one you already have (including suppressors). Mags are generally cheap, so get what you need as you're able.
At bottom, the G34 is the only thing you've suggested that includes an actual planned use of the gun, and it's the only thing you've mentioned that allows you to spend quality time with a family member. That, to me, makes it a good use of $650.