Hi there... don't rush to re-home the tetra's ... take a look at my signature and see what I'm keeping with angelfish and all is well. My angels arrived
after the smaller tetra's and harlequins and so they've grown up together. They've grown up seeing the smaller fish as family and not food. I've seen and heard of this done many many times with no issue. The problems generally arise when you try to add new small fish once the angels are adults ... new arrivals arn't family and so
could become food.
Recently though I added some new young harlequins and I added them with held breath as technicly my, now adult, angels could have just swallowed them whole but they left them be ... I got away with it and perhaps because they were the same as the harlequins they'd grown up with - I was just adding to the shoal and the new young harlequins just joined the older adults.
I keep my fish well fed - they have always been fed twice a day and so they know food is coming as so never get hungry enough to see smaller habitants as food.
I think you are sensible to be aware that the angels might decide to start eating the tetra's - being aware it
could happen is sensible but I honestly think the likelihood of it happening is very very slim. I think seen as you are aware it's better to watch and wait. If the tetra's start disappearing one by one then re-home them. I would possibly look at adding to the silver tip number whilst the angels are still young as once they grow you could see a problem adding.
If you decide to re-home though and replace with another shoaler then look to the larger tetra's and the deeper bodied tetra's. Emperor's are good as they're too big to be food. They're also safe on the angels fins as they are not fin nippers. Some of the other tetra's can be nippy. I looked at black widow tetra's as they are deeper bodied but they are also notorious fin nippers and so whilst the deeper body was fin for the angels - the fin nipping wasn't.
On to the other stock - if anything needs to be re-homed from that list I'd look to the shark. It will eventually out grow the tank and it's also too aggressive and hectic in behaviour for the sedate angels. I think you will have problems in the future with this fish and it's best to re-home now if you can. See what other members think though ... don't just take my word for it.
The angels - I wouldn't add anymore for your tank size. I also have a 4ft tank (Juwel Rio 240) and had four angels. I ended up with a pair and 2 spare females, one of which turned aggressive to the others and so now I just have my pair. I would not have been able to accommodate any more angels as now they are adults it's obvious there just wouldn't have been enough space for territory. Should you get a pairing up you may find you have a difficult choice to make as I did.
Hopefully that info is helpful for you. Good luck with the angels