In the log I see things like:

    2017-09-13 03:54:33 init message: Rescanning...
    2017-09-13 03:54:33 Rescanning last 68616 blocks (from block 416339)...
    2017-09-13 03:54:40 AddToWallet xxxxx  update
    2017-09-13 03:55:33 Still rescanning. At block 418849. Progress=0.549138

I would be interested to see the wallet file name on each of these log lines.

Would there be any interest in merging such a PR?
{
    CAmount nTotal = 0;
    {
        LOCK2(cs_main, cs_wallet);
        for (const auto& entry : mapWallet)
        {
            const CWalletTx* pcoin = &entry.second;
            nTotal += pcoin->GetImmatureCredit();
        }
    }
    return nTotal;
}
CAmount CWallet::GetUnconfirmedWatchOnlyBalance() const
{
    CAmount nTotal = 0;
    {
        LOCK2(cs_main, cs_wallet);
        for (const auto& entry : mapWallet)
        {
            const CWalletTx* pcoin = &entry.second;
            if (!pcoin->IsTrusted() && pcoin->GetDepthInMainChain() == 0 && pcoin->InMempool())
                nTotal += pcoin->GetAvailableCredit(true, ISMINE_WATCH_ONLY);
        }
    }
    return nTotal;
}
CAmount CWallet::GetImmatureWatchOnlyBalance() const