Pruning decisions

[JT101]

Hi everyone.

I've inherited some dilapidated trees. I wish I could find someone at the allotment who really knows something about trees, but most people are "have-a-goes". I've done some training myself, but wanted some others opinions.

1) So the first one in Photo 1 (photos have attached in reverse order), I'm not sure exactly what it is. Will be either an apple, pear or plum though.
Anyway, I think it's got a case of the codominant stems. You can't see it in the photo, but the two main stems have a really tiny trunk below the grass there. Probably was bought to be trained as a fan or espalier and sent off in two directions, but ended up getting planted as a bush. I say this because I have one identical in my garden that I bought which does this.
So my inclination is to remove the right hand stem completely, and then remove the central leader on the left one down to the red line to create a goblet shape. At the red line, there appears to be a side shoot 1/3 the thickness of the central leader.
Does that sound ok? Or should I shape it to a goblet as is, and retain both trunks?

2) Second one in Photo 2 I'm pretty sure is wild plum owing to the spikes. My first question is, do the spikes becomes branches, or fruit or what, or do they remain spikes? You can so the one I've highlighted which looks like it used to be a spike.
In photo 3, the portions I've highlighted are what? Is it last years growth? It must be because it has the remains of some plum seeds stuck to the end. Presumably I want to cut back to 2-3 buds then?

3) Finally photo 4, it' not easy as you're not there and it's a bit of a mess. There are suckers everywhere, it is a mess, and far too tall, but it is oddly productive. Well I see a lot of remnants of plum seeds all over it. Certainly the low branch 1 to the bottom left needs to come off as it's not doing anything. Trunk 2 & 3 both seem ok, so even though they are seperate, it may be a bit drastic to remove one or the other. Trunk 3 is quite a nice overrall shape.
The real question is of the two leaders from trunk 2. Apart from being codominant, they get entangled higher up. I'm inclined to remove a whole one of them?. On a mature tree, would that be ok?

I am open to any comments if my ideas are misplaced

Thanks

[Green Aura]

I can't advise you on chopping whole bits off as I'd be far too scared. I did, however, have a thought which might be worth checking before you get out the saw. Are there any grafts? If so could these be family trees - you know the ones where two different apples, plums etc are grafted on to one stock. If I were planting trees in an allotment I'd certainly be tempted you get a close pollinator and variety without using too much room.

If you haven't seen them in fruit my advice would be to just tidy them up a little and leave them for a year to see what happens.

[Broad Bean]

I second a level of care until you know what you have. Also, plum trees should be pruned in the summer so not a good time now - they're liable to infection at this time of year. I'd just remove and damaged or diseased wood and keep an eye on them for now.