If someone gets access to your Coinomi wallet it's obvious that he/she will have access to your private keys without any difficulties too.
Getting access to the private key will require tools like Iancoleman as private key can not be gotten directly from Coinomi, correct me if wrong. But the seed phrase can easily be revealed directly on the wallet which is enough for another person to steal the bitcoin and all altcoins leaving the wallet compromised.
You should use Biometric security to protect your phone so that no one can access it but only yourself
Password is safer as DaveF commented, if only password is used, can the wallet also be accessed if the password is unknown, it will be difficult. Also what if you are sleeping and someone that is close to you make use of your finger to be unlocking your phone, apps including your wallet to compromise it. Biometry can be good for easy access, but not as secure as passwords.
Also do not forget to save your private key somewhere safe aside from your phone,
Yes, but while private key which you cannot get directly from Coinomi, you can save the 24 words passphrase offline and having like three copies at least in different locations.
if you have two email Ids maybe gmail and outlook then you can send it from your one email to another so that you can have it forever in your two emails.
If you email is compromised, then your seed phrase or private key or the backup is revealed whcih can be used to compromise your wallet and lead to coins stolen.