Will we (or loved ones) become angels when we go to Heaven?
No. Angels and human beings are entirely different creatures (Heb. 2:14). Jesus said after our resurrections we will be like angels in that we will not be married (Matt. 22:30). But this was a specific limited comparison. It wasn’t an indication we'll become angels, or a statement that we will in general be angel-like. Angels will always be angels and people will always be people. Humans are eternally human. Death involves relocation to a different place and transformation into better humans (Rom. 8:23), not into nonhumans.
For more information on the subject of Heaven, see Randy Alcorn’s book Heaven.