I have an O-A visa, which gets extended every time I do a border run with my teenage-daughter, who has an O visa. The visas were issued in Los Angeles, who said dependent visas could only be issued in Thailand. Thailand Immigration said I need to reapply for an O-A at the same time I apply for a dependent visa. Can anyone tell me the best way to accomplish the dependent visa? If I reapply, do I need a new police report from here? I'd appreciate tips.

You have an O-A long stay multi entry visa that gets a new one year permitted to stay stamp on each entry?

You can not obtain such a visa here - you can obtain a one year extension of stay for retirement from immigration with 800k in Thai bank account or proof of 65k per month income. A dependent extension of stay can only be issued in Thailand.

You are aware that any travel after your visa expiration date (the date on the visa itself) will end your last permission to stay unless you obtain a re-entry permit first?

Your daughter will need to obtain matching extension of stay based on your stay at some point if you do not plan to obtain new visas in the US.