So aside from the big conversation of “kids in bars”, my suggestion would be to try the Boston Public Market, inside are some food vendors, a bar, and a decent selection of New England beer to purchase.

It’s a mile or so from Trillium.

Lots of gluten free options, I’d say at almost all popular restaurants in the area, whether or not they prepare the food in a spot where there isn’t cross-contamination is questionable.

La Famiglia Giorgio’s is probably a good option.

No secret children’s menu, but I believe they’ll try their best to accommodate if you ask for tweaks.

There is food but I wouldn’t call it kid friendly. Look up the Fort Point menu on their website.

If your kids are well behaved and have an adventurous palate, they might be ok.

Ricky’s in Somerville is probably an option, maybe a mile walk from Central. They have a small amount of parking and there’s a bus stop near by.

Boston is not huge, but rent prices sway dramatically depending on location. You should do research in terms of what neighborhoods you would prefer, and then search based on that.

That being said, studios will be on average $2000/mo, 1br $2500/mo, 2br $3000/mo, although it all depends on the location and features.

Paying extra just because you want guests in their own bedroom is quite kind, but it's probably not the best idea in the long run vs. having them sleep in the living room.