I need some help understanding my current situation, if anyone has been through this, or knows what needs to be done.

Background - I am a foreign national working in Thailand, holding a Non-Imm B visa. I gave birth to a son this January and I checked with Immigration about his non-O visa, they said to get it once he leaves the country before he comes back.

We're visiting home (Ireland) for 15 days this mid-July, so we would need to apply for his non-O while we are there so that he can have it when we're back in Bkk.

Here's where I have a few questions:

1. I cannot apply for it when we're in Bkk, I need to wait until we reach Ireland to apply for it. The consular says I need 15 working days for the visa to come through, but Thai eVisa says it's 3-10 working days. (Going to the consulate is also not an option because the only one for the UK and Ireland is in London.) We don't have 15 working days, so can I actually apply for it anyway before we go?

2. If yes, the online form asks for proof that he is in Ireland. I emailed the consulate to ask what I could use to prove this. They replied with "local utility bills," which obviously he won't have. For this, could I just use my Thailand rental agreement? But that won't prove that he's currently in Ireland, so I'm unsure what would work here.

3. If I can't get the visa on time, he can obviously come back visa-free, but I don't know the process to change that to a non-O dependent visa - if someone could share that with me.

Thanks in advance for any help I can get.