A good answer here is specific and boring: your funds stay in your exchange account, the API key has trading enabled and withdrawals disabled, and you can revoke the key yourself at any time. If the answer involves transferring tokens to someone else's wallet, that is not automatically wrong, but it changes the risk profile entirely and should be priced accordingly.
You should be able to name your spread, your depth, your maximum order size, and your inventory ceiling. If a provider cannot tell you the hard limits on their own system, they do not have hard limits.
That last question is the one teams skip. A quoting strategy needs inventory on both sides of the pair, and that requirement usually dwarfs the subscription or retainer. Get the number before you sign anything, not after.
Some answers should end the conversation. Treat any of the following as disqualifying:
For the fundamentals, read the guide to crypto market making, or see how a bot runs on a specific exchange or chain.