Switch questions

Hi

The customer I am working with have an RPQ approved to use their own switches for Hare/Rabbit.  They want some clarifications on the below.  Please can you help?

- They want to use DAC cables, this means they won't be using Dell EMC provided SFPs.  Do we foresee any issues - performance or otherwise?

- They are currently planning to get the install done with one switch and later provide 2 new switches (one to add and one to replace).  There will be degradation when the old switch is being replaced.  Do we foresee any issues?

- Must the hare/rabbit switches support vPC? 

Also, if any of the above is possible and will have no major issues - do any of these need a fresh RPQ?

Thanks in advance for any help.

Regards, Ram.