After consulting with devs here is the answer to your questions:

getauxblock returns ChainID. In case of Crown it is  "chainid" : 20

Any other MM coins that have a conflicting chainID can not be merge mined together.

The problem seems to be specific to these two mentioned examples, probably because of same chainid - would be awesome if you could check if it is also "20" - and thus is not a general MM problem caused by Crown code / mining.

the code relevant to auxpow mining is to be found here https://github.com/Crowndev/crowncoin/blob/master/src/primitives/pureheader.h

Here is an (old) list of chainIDs https://bitcointalk.org/index.php?topic=769073.0

Crownfan

Thank you for the information, we are looking into this.

Team CrownCentral would like to announce that the new CrownCentral API is now up and running! Check it out and monitor the rewards of your System- / Masternode. Charts, weekly earnings notifications and more! https://crowncentral.net/

Enjoy!

Crownfan

Hello beliomir, systemnodes will take about 6-7 days to pay you the first reward at current node count, after first payment you should get rewards approx. every 2.5 days.

Masternodes will take 2-3 days to pay you the first reward, after that you will receive payments daily.

If you want more information about our proposal system, you can visit our website https://crown.tech and our forum https://forum.crown.tech

You can also join us on mattermost, our central community and chat site: https://mm.crownlab.eu

The error you get may be due to systemnodes that were programmed for reward but dropped from the network.

The finalbudget is only generated 2 days before the superblock, so you cannot vote fnbudgets at other times of the month.

Best regards,

CrownSupport