Upgradable Contracts that use ERC20 non upgradable tokens

Support Upgrades
1

If an upgradable contracts token is upgradable e.g. using UUPS, must the token be upgradable even if it does not inherit it but imports it?

import {PToken} './Token_NonUpgradable';

contract A is UUPSUpgradeable {
    mapping(bytes32 => PToken) public pTokens; // pointsId => pTokens
}

Will there be any problems?

2

That seems fine, since your contract is not inheriting the storage layout of the non-upgradeable contract.