It’s possible to enter thailand on an expired Thai passport. She’ll need to renew it in Thailand before she can depart again, and it will cost 1000 baht to have to done in 3 days (3000 baht for same day service). This assumes of course she is fully registered on her house registration and has an up to date valid Thai ID card which is what is needed to get a new Thai passport

Well, if you are based in Thailand more that 180 days per year then you become a thai tax resident. Thai tax law states that any income remitted into Thailand in the same year it is earned is taxable in Thailand, subject of course to foreign tax agreements.

Check this out

now they are in the system they’ll need the standard documents. But this bloke is a bit of a special case. Overseas born Thai citizens can’t get on the house registration immediately like locally born kids so embassies can bypass the need to be in the house registration for an overseas born Thais first passport

That is in Thailand. Embassies issue passports to overseas born Thais all the time.

You need to get your first thai passport back in the UK. Without an ID card you can’t apply for a passport here in Thailand. Embassies can generally issue your first passport without an ID card

You are Thai. Where were you born, in the UK or Thailand?

Check out this link, it may be helpful

Simple answer is yes. Enrolled in a school with the proper credentials, documents supplied by the school, 500k per child in the bank and an extension is possible.