Ajax will be able to do everything after amputation that he can do now.  I'm very curious about whether this is actually true,

 

I know you have your furbaby Ajax's interest at heart first and foremost or you wouldn't ask the question.  But to answer your question about "is it true that he can do everything still".  Yes.   Your vets are telling you the truth.  I know you just need reassuring.

I can tell you this firsthand as a person who has had a 3-legged dog for 11 1/2 years (front left leg birth defect but it doesn't function even tho it's still attached).  Comet has emotional problems from being from dog hoarder, even after all of these years.  So, I don't think of her being 3-legged because of her emotional problems.  However, when she is in her comfort zone, she is and has been one of happiest dogs ever!  Her pictures always reflect a happy dog. I think because of her smile, she is the most photogenic dogs I've ever had!  I've included a video of Comet when she is 9 or 10 years old jumping on and off the couch and standing on the arm of it.  She still even runs up the stairs in our house – at almost 12 years old!  I hope it will answer your question of quality of life.  

Personally, if I knew I cure the cancer – there wouldn't be a question in my mind on what to do.  But I also know that being 3-legged is no big deal to a dog.  Cancer is a big deal.   Since being on tripawds, I see this every day.   We also see people looking for other options and typically they fail.  (based on what I see here)      

Whatever you decide, we'll stand by you 100% because it is a decision you made out of love.  And that's the most important thing.

P.S.

The puppy question:

Comet is a sassy, spoiled little girl so she has been difficult each time I bring one in.  I've done it twice.  Once when she was 2 years old but Rugby died from cancer last year.  Second - just last year after the death of Rugby. (Rocket, aka monkeybutt) She may hate it at first, but she also can't live without a companion and ends up loving them very hard.  When Rugby died, I thought she wouldn't survive the emotional trauma.  And although Rocket is mostly a nuisance and irritates her to no end, she still loves him a lot!  I know this because one day he didn't feel well and he was in his crate.  She sat in front of his crate and kept barking at me to check on him.  She wouldn't stop until I came over to see if he was okay.   

I'm glad you "got" the inside joke about Comet!  Once you've been here a while you'll find Comet knows "everything"!  And you know why?  Because she got her vet degree from Google University!

I know it can get depressing reading the site.  But trust us, for every 1 sad story, we have at least three happy stories!

she said she would be "very surprised" if he was significantly limited in his endurance or only able to take short walks. 

 

I can say that when Comet was 8 she still had a lot of endurance, but keep in mind her back leg muscles are that of a body builder and she is only 38lbs.   She's knows no better and she was still very puppy-ish until a year ago when she got that infection in her neck disc.  She then slowed down and started showing her age and her 3-leggedness.

I wouldn't worry too much about what a vets says on those issues. Keep in mind also, that since a dog has to hop, they stay in shape.  It's a workout for them just to get around.  I haven't found one vet that has understood what it's like having a 3 legged dog.  I even asked once if there was any long term studies on dogs with 3 legs and I was told - no.