Any contrary views/other suggestions?
I wouldn't drop/swap any of the runs. Just add the cycling as necessary, most training plans have the option of doing cross training.
4 months is easily enough time to build up to being able to finish a HM given what you're written so far (whether you'll be as fast as you wanted to be is another question, given you're coming back from injury then you just need to accept that you probably won't be).
Looking at the 16 week beginner (BUPA) marathon training plan on my desk (I'm doing a hybrid between that and an intermediate plan) it says:
* To get the most out of it, you should already be able to run at least 5km, and ideally 10km, comfortably before starting
* The first HM length or greater run is a 15 mile run at the end of week 10
so that's 5km (ideally 10km) comfortably to more than an HM in 10 weeks.
The intermediate plan (starting with being able to do 10km comfortably) has a 13 mile long run at week 6.
Have a look at some Half-Ironman training plans as that should cover what you need (HM, 90km cycle, etc) and just ignore the swimming (but do some if you can as it's all good for fitness and recovery). You'll find they have just as much running as a traditional HM plan but also throw in a load more cycling.
The gentle ramp up in distance/time on feet is important though. I'm lucky that I can get away with more than the usual suggestion of limiting it to 10% increase in time/distance a week.
I started my marathon training on Jan 7th where I got round a 5km run comfortably but would have struggled to carry on to do 10km comfortably. Yesterday was the end of a week where I did 5h47m of running including an 18km long run; although it was a bit of an outlier week as I had two long runs (Monday and six days later Sunday) as I had to move the long run from the week before a day later into this week. Legs feel quite tired today unsurprisingly, but a 1km swim and that time in cool water has helped ease them a bit.
I've got my first HM distance run on Friday (extended commute into work). Looking forward to having done that run!