@Jocelyn456
It sounds odd to me. I host long term stays and, although I do occasionally get bookings for them a bit last minute, it's unusual. Guests staying that long tend to book at least a few weeks, if not months, in advance. Of course, that all changed with COVID, but I am finding that bookings wise, things have gone more or less back to normal patterns for now.
Of course, there are genuine reasons for a guest to book a long term stay last minute. I have had perfectly good guests who needed to because they had a host cancellation or because the new home (renting or buying) that they were planning to move into has been delayed, but then they usually provide an explanation of that in their booking. Also, I live in London, where there is a high demand for long term stays compared to areas that tend to attract only holiday makers in general.
If you get a series of similar, strange requests, yes I would suspect that it's a scam. If you are not using IB and they are only sending enquiries, you don't need to do anything. Just respond to the first message. I would not accept bookings anyway until I had sufficient information from the guest as to the purpose of their stay etc. and a good feeling about them through a few messages back and forth. If in doubt, it's best to say no. It is tempting to accept if you know a quiet period is coming up, but it's not worth the risk in my opinion.