Is it possible to learn the following maths modules in one summer?

M1 is very similar to the mechanics portion of AS physics, you probably have quite a solid grounding in it already. As for FP1, that will take some more commitment, but with predicted grades like that, you ought to have the aptitude to take on less familiar topics like complex numbers and matrices, both of these are more about procedure than derivation. Other FP1 topics should be familiar to you already, just a little bit more in depth. If I remember correctly C3 has coursework which you'll need to take into account.

Thank you very much, I do OCR so I don't have any C3 coursework.

I'd suggest you do it - I don't know your exam board for Physics, but I did both Physics and Maths on Edexcel and most of M1 (and even some of M2) was just a harder version on the mechanics topics covered by Physics AS and GCSE (e.g. momentum, kinematics, moments etc.) FP1 really isn't that difficult, and although some of the content like complex number and matrices will be completely new, the questions on it aren't too challenging. Again, doing 1/2 of C3 and C4 won't be difficult, though I did personally find the integration in the second 1/2 of C4 needed a lot more practice than the other topics did.

If anything, the hardest part is motivating yourself to learn 2 1/2 modules over the summer. But your predicted grades suggest you're a fast learner, so you might even be able to get more done in the time. I self-taught my maths and further maths A levels so I'm speaking from experience - it really isn't that hard so long as you make a timetable and stick to it. The extra preference that unis will give you for having done FM for economics far outweighs the difficult of doing it. Hope it goes smoothly for you