How would these somewhat rare boys' names go over in the UK?

Cedric - Little Lord Fauntleroy
Chester - American
Ivan - Sounds fine to me
Kieran (not really rare, I know) - Popular enough here as well, so fine.
Laszlo - Only suitable if you're from a country where this is a normal name
Malcolm - Probably OK. Popular in the 1950s but not too popular
Marshall - American
Maurice - 1920s and it hasn't come back into fashion
Munro - Would be OK in Scotland. DH has a friend with this name.
Rye - Unusual, maybe better as Ry, so we don't get mixed up with the cereal
Trevor - Very 1950s and not due for revival any time soon.

Cedric- Reminds me of a snail, Old fashioned
Chester- Is a cat's name.
Ivan- I like this name, not often used. Seems eastern european.
Kieran - As you say, very common. I would associate it with Irish roots.
Laszlo- Seems a bit 'made up'.
Malcolm- Accountant.
Marshall- Very American.
Maurice- Also American.
Munro- Scottish.
Rye- Bread.
Trevor- Very middle aged.

The only pretentious ones are Laszlo and Munro. The others are generally a bit 'odd', though uncommon apart from Kieran. I would go for Ivan out of this list.

I know three little Chesters! I also don't get the rhyming slang and in any case you could rhyme any name with something offensive if you tried.

Rye is a nn for Ryan in my book
Least faves from your list are Cedric and Trevor

Chester is my fave. I've met two little boys named Chester, both lovely.
Never come across a dog named Chester. I think it's a bit silly to say any name is a dogs name though

I googled 'Chester Cockney Rhyming Slang' - I have to say that I have never heard that connection before and cannot believe that it would occur to any more than a handful of people in the UK. If the full name was going to be Charlie Chester, maybe it would be more of an issue - as it is, Chester is fine and quite sweet. Way better than Trevor, anyway!

I like Ivan the best.

And Steve/Daves!

Apart from those you've got some good unusual choices (apart from kieran which is very common and a bit naughty boy/Chav in my opinion)

I like Cedric, but you MUST lose Trevor and possibly Malcolm.

Really hard to imagine a baby Trevor or malcin the uk as those really 70s bloke names are now fat, balding, middle managers, along with the Nigel's, Barry's and

Chester is a lovely name :)

In the UK, they are not similar types of names at all. Cedric belongs in an Edwardian children's book. Malcolm is old fashioned. Trevor is working class blokey and Rye is a kind of cereal.

Cedric and Chester - not my favourites, sound a bit like pet names ie dogs.

Ivan - again not one of my faves but perfectly nice.

Kieran I'm Irish - I know a lot but really like it.

Lazlo - would assume Casablanca connection

Maurice, Trevor, Malcolm, Marshall - dated and a bit try hard. Trevor in particular I feel would lead to teasing in school.

I like Munroe and Rye

I like the name Trevor, I think its cool in a Stanley type of way.

Just as a side thought really - if kids actually bully (rather than just teasing, whixh every child will probably experience) due to a name, would that not be because their parents have commented on / laughed at the name. Kids will see a classmate, hear the name Cedric for the first time and move on, no? It's only when someone tells them its a weedy/dated name will they pick up on that.

I like Cedric best out of that list. As a Scot I'd say Malcolm is OK but old fashioned and Munro is more of a surname (kind of name an American with Scottish heritage might use), I'd go for Murdo or Mungo in preference.

Sorry, I think they are all awful

I know youngsters with each of the following names:
Chester, Ivan, Maurice
They all suit their names (as people tend to in the end!).

I've heard of a Marshall and a Munro.

Haven't heard of a Rye before but I quite like it. I don't imagine any of these being picked on particularly but that might be because I live in a very multicultural area of London and anything goes.

It completely depends where you are going to be living and where he will be going to school. Most of these names (with the exception of Kieran) will be bait for bullies outside of very middle class areas. I love Lazslo (Hungarian, right?) and Ivan. I wouldn't worry too much, if you love a name, go with it. See what he looks like when he makes an appearance.

Tbh, not keen on these. Ivan is ok. Trevor and Malcolm are for much older age groups. Maurice - I know a 40 year old who shortens it to Mo.

I like Cedric.

Also Malcolm and Kieran are quite nice.

Trevor is awful.

All on the fucking awful end of awful.

They are all horrible names.

The best three are:
Kieran (Agree better with a C - but dont want to offend any K-lovers!!)
Malcolm - not overkeen but quite like 'mal'
Laszlo -quite quirky - quite like it

Really cant understand why anyone would use Chester (its cockney rhyming slang - google it).

Favourite three would be Ciaran (with a c), Maurice and Ivan.

Cedric - posh and wet
Chester - a dog's name or a place
Ivan - OK, might get "Ivan the Terrible" comments
Kieran (not really rare, I know) - quite a nice Irish name, prefer the spelling Ciaran
Laszlo - harsh
Malcolm - old-fashioned
Marshall - surname
Maurice - old-fashioned but I quite like it
Munro - too surnamey
Rye - strange
Trevor - unfashionable

Kieran is possibly most common boys name around here, 3 or 4 of them in DS's yr at school. I thought it was on the MN list of Chav names, too.

Posh: Cedric, Ivan, Laszlo
American: Chester, Marshall
Scottish & odd if you're not Scottish: Malcolm, Munro
old-fashioned: Maurice, Trevor
Weird, will get mistaken for Ryan: Rye

Cedric is dreadful. Don't like any of them very much. Ivan isn't too bad. Kieran isn't bad either. They must just be not my sort of names. Munro and Rye. No. Made me think of Munrospun tweed and Rye bread.