If the two keywords are closely related or the synonyms (e.g. 'wheat bread' & 'raisin bread') the you can target both to the same page else otherwise having dedicated pages can be good idea.

I try and target 3, sometimes maybe even 4 keyphrases per page.. You should always be targeting more than 1, it's just they need to be closely related. Don't try and target Blue Widgets and Yellow Widgets on the same page..Target Blue Widgets, Cheap Blue Widgets, and Best Blue Widgets on one page, then Yellow Widgets, Cheap Yellow Widgets, and Best Yellow Widgets on another page.. So on and so fourth..

Yeah, Targeting 2 keywords in one page is not advisable. It is better to take 1 keyword to the exact match domain or url. Base on my SEO journey the best way is 1 keyword per page or 1 target per page.

Cheers

You can only really target one keyword per page with on-page optimization. Sure you can use backlinks to target variations or synonyms, but one keyword is really all that's possible with on-page.

It would be be difficult to answer your question or give you suggestions without seeing the website in question, but It's generally easier to rank when you target one main keyword per page and target their long tail variations on their respective pages.

If both keyword are of same niche go head. Infact targeting more keyword per page is good, if you target 1 keyword and your anchor texts have same keyword then it will hurt ranking. better you use multiple anchor text in backlink and for that targeting more than 1 keyword helps you.

If both the keywords are related to each other and are of same category, then you can target the two keywords in one page. Otherwise, target the second keyword on the another related page.