A few thoughts that may be helpful (hopefully!)
-re. the mortality associated with c-section vs vaginal delivery, the numbers do seem a little frightening when you look at as it's been presented to you. Those figures do include the 6 weeks post-natal period though and include things like infection, blood clots etc, not just 'deaths on the operating table', so if you do chose a section don't go into it thinking there's a 1:4000 of dying on the spot! Another way of thinking about it though is that current numbers show 1:4000 chance of mortality with a planned section, that means 3999:4000 chance of not dying.
If mortality for a vaginal del is 4:100,000 (1:25,000) and for a section is 25:100,000 (1:4,000), then for about 99,980 women per 100,000 the outcome is the same irrespective of the mode of delivery and nationally IIRC there are about 100,000 elective sections/year (convenient for the maths!) so for the enormous majority of women the mode of delivery doesn’t make any difference to whether they survive or not. Clearly every death related to childbirth is an awful thing, but you’re actually looking at an incredibly rare event either way.
These numbers are for a 'whole population' though, and for some women it's obvious from the start that they have factors which may increase/decrease the risk (often women with cardiac problems/pathological placentas/other odd stuff that crops up in pregnancy).
The rare risk of dying also has to be balanced against the risk of morbidity ('non-death' complications, like tears, bleeding, infections, psychological trauma etc) for the of women who don't die, and the relative risks may be significantly different with the different modes of delivering. One thing that no one seems to have commented on (although maybe I've missed something along the way) is that you've had a colorectal surgeon involved in this decision making process & that kind of begs the question of whether there's something else that needs factoring in that has been a bit glossed over in this thread that that rather than the bleeding risk might be the really important thing.
-re. having 'the drip' post-partum. It's used for uterine atony for both sections and vaginal deliveries so not having a section doesn't necessarily mean you wouldn't need it after delivering. The drip usually only lasts for 4 hours though (and it's worth remembering that the numbness from a spinal for a section would be working for quite a bit of that time, and even once it's worn off the other analgesic component of the spinal will still be helping). Some units though use a long acting analogue of oxytocin as a single shot (so essentially equivalent to 'the drip') for all women having a section and it's not flagged up AFAIK as being an increased risk of post-op uterine pain compared to having a single shot of short acting oxytocin (which is what other units use) so it may be that having a longer the infusion also doesn't make much difference to post-op pain.
-re bleeding, there's lots that can be done whatever mode of delivery someone choses if they're known to be at higher than usual risk (and often just planning for the worst means it doesn't happen!) so depending on the exact risk factors and what happened last time there may be other things that they can do to reduce the chance of a haemorrhage again (in addition to planning to use the synto drip). It is worth remembering that what most normal people think is a lot of blood is quite different to what most HCPs think is a lot! 2.5L is certainly a proper haemorrhage, will trigger the emergency protocols etc and absolutely it'd be best if it didn't happen, but it's also well within the realms of what an obstetric/anaesthetic/midwifery team will be used to managing if necessary (and the fact you survived the last time is a pretty good indicator that you'd survive again if it were to happen this time!). For some women there's some comfort in planning a section because it means that everyone's already in the room to deal with bleeding if it does happen, but for others the attempt at a vaginal delivery that might go smoothly, but equally might not, is worth it even if it does end up with a bunch of us barrelling into the nice quite labour room to fix a bleed in the end.
-ultimately you really cannot plan for everything in childbirth and you only know it is going to be normal (by either route) after it was normal. Your team can advise you re the relative risks for you as opposed to the risks for all women, but ultimately quite a bit of it comes down to what risks you're comfortable-ish with and what things are most important for you.