You can use eSignal's data in TWS. If you are trading futures, around 3 years ago, eSignal changed the symbols (added an extra zero, or something like that), and the futures quotes could no longer be seen on TWS.
I got around this by creating an eSignal Watchlist, and placing it side by side, essentially blending it (like same font & everything) with the TWS Watchlist, that lists the futures contracts, but no quotes. So I execute on eSignal's charts, see my quotes/other on the eSignal platform. And see my P&L on TWS, right next to the eSignal watchlist. Stocks are fine.
If you are just using eSignal for market data, and you trade futures, TWS will not show any quotes. And the only way to get around this, is described above. I already spoke with IB support regarding an updated plug-in, so that the futures quote issue could be fixed. After lengthy conversations, back and forth, they told me straight out, that it's "not on their priority list", meaning that they will never fix it, and being honest about it: it's never going to happen.
In terms of technical questions, I would just call eSignal, as they have good customer service. IB, not so good.
Data's speed should be perfectly fine...