Mummsnett I'm in a similar boat - 33 weeks with a two year old. I'm vulnerable, more due to asthma than pregnancy, so DH has been doing all shopping and we've both been wfh since Paddy's day.
As I'm sure you know, groups of up to 6 are allowed to meet outdoors in NI now, so long as they remain at 2m. There's no distance restrictions for travel within NI.
My PIL (70s, so more vulnerable than anyone in our household) came up yesterday for a BBQ and I have to say it was one of the loveliest days I've had in a very long time. The adults all stayed at 2m, and none of us have been anywhere so the chances of us being infected are slim. PIL brought their own plates etc, we sat at different tables more than 2m apart. They only went inside to use the downstairs loo, which I cleaned before they arrived and after they left (we used upstairs).
We were happy for them not to distance from DD since she's so low risk, and they were happy to get close to her since she hasn't been anywhere other than our walks. Obviously there's no way a two year old will social distance so that was agreed in advance.
Wrt meeting your parents, if they've been following the guidelines then they're very low risk to you, and meeting them outdoors is allowed now (although obviously if you have the toddler with you, social distancing could be tricky - a walk with the buggy maybe?). Pregnant women were included in the vulnerable group as a precaution. The risk is more likely to be to your parents, especially if they're older, and even more so because your DH has been out working so your household is more likely to be infected than theirs. Similarly, I'm more worried about picking covid up in the hospital and passing it to PIL who will likely be caring for DD than them bringing it to us. The risk to both me and the newborn is very very small indeed.
I've found the RCOG guidelines helpful, they have some very informative stuff on their website.