your biggest issue I believe when you get to poipet is the time frame before you fly out of Thailand as it looks like it's in 47 days which is well over the 30 days. If they want to deny you that's a good reason. Have you got your train to Laos ticket already? If so you might need to flash them that. I'm not saying it will be ok but if the IO has any decency about them you should be ok.
have no idea my man. I've not gone through that border since 2015 but reading everything in this group it's almost like going into Tijuana from the USA. Push a button and if it's green they let you in and if it's red they don't. I thought they only denied serial border bouncers but this Ellie says other types of travellers are getting denied to
If you want 150 days you can do what I just recently did. 60 day visa, 30 day extension, 2 land border runs. You can get another extension after your first visa run if your landlords cool enough to do another TM30 after your border run but my landlord is a slack ass so I did 2 border runs. Either way will be fine for 150 days