Advice needed re upsampling

[MarieMeyer]

I'm helping a family get ready for a memorial service. They have some photos taken with a 3MP camera; they'd like to print them at 8x10 or 11x14.

Adorama indicates that minimum for 11x14 is 240 dpi, which works out to 2640 x 3360 pixels, or 8.9MP. But, the files I have are around 1375 x 1750 pixels.

Is there an upsampling routine in PS that is worth trying in this circumstance?

Also, I've read about doing upsampling in a sequence - first going up to 5.5 x 7, then up to 8.25 x 10.5, then finally 11 x 14. The theory being that a series of smaller upsamples is better than one big one. Any substance to that idea?

And, finally: is there any way to preview on-screen the amount of pixelation I'll get before sending the files off to the lab?

[Nancy OShea]

Tryt AI Gigiapixel from Topaz Labs.  Keep in mind that any bi-cubic, etc... up-sizing of low quality images usually introduces a lot of unwanted artifacts.  But this tool claims to be radically different, using machine learned intelligence to fill in the missing data.    A free trial is available too so give it a try and let us know how it works for you. 

https://topazlabs.com/ai-gigapixel/

Free Trial

https://topazlabs.com/downloads#standalone