Welcome to the forum. 
No. MRC format only. The .gain files output by EPU are internally TIFF files, so can be converted with various different EM programs, although I find I generally get better results generating a gain reference from the raw movies.
As for the defect lines, you can either provide a defect file (four column plain text) or edit the gain reference to set the defect lines to be zeroes - per discussion in this thread - that acts the same as a defect file for CryoSPARC.