For devs looking to build on testnets, the Ethereum Foundation will be winding down support for the Rinkeby, Ropsten, and Kovan networks after Ethereum's transition to a proof-of-stake model. To ensure that your testnet applications remain fully functional after the transition, we recommend using Goerli, which will remain unchanged.
A transaction object will have a block number associated with it, the block number is Ethereum's measure of time, however, if you want a standard timestamp you can easily get that by making a call to eth_getBlockByNumber and specifying the blockNumber field. If you only have the transaction hash, you can get the full object by making a request to eth_getTransactionByHash.
A super easy way to distinguish between these two addresses is by calling eth_getCode, which will return contract code if it's a contract and nothing if it's a wallet.
Don't worry, we got you. Check out our support page for plenty of options!