The clamp you linked is made for aquacomputer aqualis reservoirs which have an outer diameter of 75 mm.
Neither the 60mm or 80 mm tubes you linked will fit exactly... can you make it work? Perhaps.

The cap you linked is also made for an aquacomputer aqualis reservoirs and is a different diameter (75 vs 60/80). The cap also does not secure to the top of the tube by threading onto the tube, instead aqualis uses an inner stainless steel tube to secure the top to bottom, with a pressure fit to the reservoir tube.

If you wish a multiport top, it may be easiest to use the aquacomputer D5 pump top which direct connects to a aqualis reservoirs, which will fit the tube clamp and the multiport tube cap you specified, as one single. integrated unit.

Edit: If you decide to go with the aqualis reservoir, there are variations in size/capacity as well as upgrades. Just search for aqualis base in their shop and you should get a comprehensive list.

Please contact the other companies for further support.

Our forum is no support forum for products of competitors.

Indeed, but to be fair, his original post was looking for information on aquacomputer gear compatibility with some equipment he had.
And then I asked him for a status follow-up in his D5 pump connection thread.
So, my bad... sorry.