1) Would it be correct to say: once the syllabus is published, CAA will develop exams, only then will training providers offer courses for the EIR / CBM-IR. Can't see the likes of Bristol or CATS offering a course, without knowing what the end target looks like.
EASA keeps a European central question bank. The questions are likely to be a subset of the current IR questions (just as the LOs are a subset of the current LOs). Give them a few months.
2) The publication linked above makes a reference to ORA.ATO.305, which mandates minimum 10% classroom time. This means at least 8 hours. If and when a course is offered by Bristol/CATS, are we likely to see a distance learning + brushup session format like the one currently in place for ATPL exams?
Can't see why not, but you'll have to ask Bristol and CATS.
3) I read in another post that the CBM-IR can only be attached to a PPL or CPL. I wonder what is the justification for this, since EASA insist it's a fully ICAO compliant IR. If one were to complete the ATPL TK (which gives full credit for the EIR/CBM theory as per publication above), then add EIR and CBM ratings to licence, can you then attach the CBM to an ATPL later on?
The CBM-IR is simply another syllabus for the modular IR, set out in App 6 of Part-FCL. There is no limitation on how this modular IR can subsequently be used to acquire other qualifications but an ATPL applicant must have completed the ATPL TK. You don't normally talk about "attaching" an IR to an ATPL, because an IR is a pre-requisite for an ATPL.