Get the METV as Steve said. You'll get stamped in for 60 days each time you enter Thailand, which can be extended by 30 days. So if timed perfectly you can get up to 9 months with it. If you want a year then add a couple of 30 day visa exempt entry border runs after the 9 months is up.
no idea, embassies can be all over the place. Laos is where people often go for Thai TVs. It's not required, you can enter visa exempt, but if you can get one it might be worthwhile.
That should work though. I'm not sure where you're staying but I'd recommend using a border run company so you don't encounter any issues. Also given the time of year right now, you could do two land border runs this year, then two next year. So an extra 120 days if you wanted. (limit of 2 land crossing visa exempt entries per calendar year).
Yep METV would be less hassle and less border runs, but you'd need to go back to the UK to apply.
get a METV from your home country. You can get up to 9 months with it, doing border runs and extensions. Possibly push that up to a year with a few visa exempt entries.
If you're looking at ED visas just to stay in Thailand for an extended period then maybe consider getting a METV. You'll need to go back to the UK to apply though. But you can get up to 9months if you time things perfectly.
If it's only 6 months you're after then a TV before arrival, with a couple of border runs and 30 day extensions should get you 6 months.
I'd recommend either one of you coming over first and sorting things out before trying to bring pets over and do everything in one trip.
Some seem to say dogs have issues here with ticks, but my dogs haven't had issues, also family who brought dogs over didn't have issues. Monthly flea and tick treatment works fine