
*****************************UPDATE******************************
Thought I'd come back and give an update on my hooligans re. walking them at the same time. Lexi is 18 months old now, Dug is almost 11 months old (and weighing in at a hefty 37.5KG

). The short story is I have been walking them together for nearly 3 months now

I did a lot of work at home, in the garden with them, walking Duggy around the garden on a lead until Lexi had no interest in mobbing him. The first time I took them out together I was worried how they would react to people/dogs/cats etc together - it doesn't matter how each one behaves when they are on their
own, being together changes everything!
The main issue with them together is pulling on the lead, changing my routes daily is a massive help with this, also with changing direction if they pull too hard and/or standing still and refusing to move if they pull. Duggy is much better at loose lead walking than Lexi
(I am so frustrated that my son ignored my protests and carried on walking Lexi on a flipping flexi-lead when she was a pup

). Dug has a gentle leader in addition to his main lead, to use as an 'emergency brake' if needed.
Cats are a bit if a problem - they both want to get a cat if they see it, so I avoid where possible & where not, I stop, back up a few steps untill the dogs are calmer, slowly walk forward & repeat as necessary (walking past cat when they are calm and paying attention to me).
They are great passing people (Duggy can be protective/possesive of me, so I am always aware of that) and having Dug about has really helped Lexis confidance, she will even approach strange men now (leashed), when in her early days with us, she would cower and try to get away. With Dug, I have to be carefull when someone is stroking him as he wants to jump up to cuddle & lick peoples faces, which is obviously unacceptable! Passing dogs is fine, the 'worst' thing is, Lexi is still very excitable so will sometime stand on her back legs, but they can be walked past dogs that are barking & growling at them with out issue, they are a little more of a handful with a loose dog running up to them - that bit is a work in progress as they both want to play.
The biggest thing is learning how each of them tick when out & about. At home, Lexi is not very food motivated (to the point of being underweight!), & Duggy is food OBSESSED. Out & about, Dug works so much better for praise and verbal direction, Lexi likes a dog treat
(I save her favorite treats just for walks
), she likes to be told 'good girl' but it doesn't have the same impact for her as 'good boy' does for Duggy.
I don't drive and the dogs were both due at the vets yesterday (routine stuff), I had nobody to give me a lift and help me, so I walked them both in on my own, 40 mins each way and some places are VERY narrow paths next to main roads. It was a little bit of a handful with them both on my own in the waiting room, Lexi barked a little at a woman that came in, but soon made friends with her and Duggy did some excited barking at some little dogs he spotted, but I did it - I feel very chuffed with myself.